diff --git a/docs/changelog.txt b/docs/changelog.txt
index f5907f4cc..aec12a96f 100644
--- a/docs/changelog.txt
+++ b/docs/changelog.txt
@@ -66,6 +66,7 @@ Template for new versions:
 ## API
 
 ## Lua
+- mouse key events are now aligned with internal DF semantics: ``_MOUSE_L`` indicates that the left mouse button has just been pressed and ``_MOUSE_L_DOWN`` indicates that the left mouse button is being held down.  similar for ``_MOUSE_R`` and ``_MOUSE_M``. 3rd party scripts may have to adjust.
 
 ## Removed
 
diff --git a/docs/dev/Lua API.rst b/docs/dev/Lua API.rst
index 1cba8284e..6eeb2dbe7 100644
--- a/docs/dev/Lua API.rst	
+++ b/docs/dev/Lua API.rst	
@@ -2528,10 +2528,10 @@ Supported callbacks and fields are:
     Maps to an integer in range 0-255. Duplicates a separate "STRING_A???" code for convenience.
 
   ``_MOUSE_L, _MOUSE_R, _MOUSE_M``
-    If the left, right, and/or middle mouse button is being pressed.
+    If the left, right, and/or middle mouse button was just pressed.
 
   ``_MOUSE_L_DOWN, _MOUSE_R_DOWN, _MOUSE_M_DOWN``
-    If the left, right, and/or middle mouse button was just pressed.
+    If the left, right, and/or middle mouse button is being held down.
 
   If this method is omitted, the screen is dismissed on reception of the ``LEAVESCREEN`` key.
 
diff --git a/library/LuaTools.cpp b/library/LuaTools.cpp
index ffeb4980a..87699641d 100644
--- a/library/LuaTools.cpp
+++ b/library/LuaTools.cpp
@@ -131,12 +131,12 @@ void DFHack::Lua::GetVector(lua_State *state, std::vector<std::string> &pvec, in
     }
 }
 
-static bool trigger_inhibit_l_down = false;
-static bool trigger_inhibit_r_down = false;
-static bool trigger_inhibit_m_down = false;
-static bool inhibit_l_down = false;
-static bool inhibit_r_down = false;
-static bool inhibit_m_down = false;
+static bool trigger_inhibit_l = false;
+static bool trigger_inhibit_r = false;
+static bool trigger_inhibit_m = false;
+static bool inhibit_l = false;
+static bool inhibit_r = false;
+static bool inhibit_m = false;
 
 void DFHack::Lua::PushInterfaceKeys(lua_State *L,
                             const std::set<df::interface_key> &keys) {
@@ -161,32 +161,32 @@ void DFHack::Lua::PushInterfaceKeys(lua_State *L,
     }
 
     if (df::global::enabler) {
-        if (!inhibit_l_down && df::global::enabler->mouse_lbut_down) {
+        if (!inhibit_l && df::global::enabler->mouse_lbut) {
             lua_pushboolean(L, true);
-            lua_setfield(L, -2, "_MOUSE_L_DOWN");
-            trigger_inhibit_l_down = true;
+            lua_setfield(L, -2, "_MOUSE_L");
+            trigger_inhibit_l = true;
         }
-        if (!inhibit_r_down && df::global::enabler->mouse_rbut_down) {
+        if (!inhibit_r && df::global::enabler->mouse_rbut) {
             lua_pushboolean(L, true);
-            lua_setfield(L, -2, "_MOUSE_R_DOWN");
-            trigger_inhibit_r_down = true;
+            lua_setfield(L, -2, "_MOUSE_R");
+            trigger_inhibit_r = true;
         }
-        if (!inhibit_m_down && df::global::enabler->mouse_mbut_down) {
+        if (!inhibit_m && df::global::enabler->mouse_mbut) {
             lua_pushboolean(L, true);
-            lua_setfield(L, -2, "_MOUSE_M_DOWN");
-            trigger_inhibit_m_down = true;
+            lua_setfield(L, -2, "_MOUSE_M");
+            trigger_inhibit_m = true;
         }
-        if (df::global::enabler->mouse_lbut) {
+        if (df::global::enabler->mouse_lbut_down) {
             lua_pushboolean(L, true);
-            lua_setfield(L, -2, "_MOUSE_L");
+            lua_setfield(L, -2, "_MOUSE_L_DOWN");
         }
-        if (df::global::enabler->mouse_rbut) {
+        if (df::global::enabler->mouse_rbut_down) {
             lua_pushboolean(L, true);
-            lua_setfield(L, -2, "_MOUSE_R");
+            lua_setfield(L, -2, "_MOUSE_R_DOWN");
         }
-        if (df::global::enabler->mouse_mbut) {
+        if (df::global::enabler->mouse_mbut_down) {
             lua_pushboolean(L, true);
-            lua_setfield(L, -2, "_MOUSE_M");
+            lua_setfield(L, -2, "_MOUSE_M_DOWN");
         }
     }
 }
@@ -2159,25 +2159,25 @@ void DFHack::Lua::Core::Reset(color_ostream &out, const char *where)
         lua_settop(State, 0);
     }
 
-    if (trigger_inhibit_l_down) {
-        trigger_inhibit_l_down = false;
-        inhibit_l_down = true;
+    if (trigger_inhibit_l) {
+        trigger_inhibit_l = false;
+        inhibit_l = true;
     }
-    if (trigger_inhibit_r_down) {
-        trigger_inhibit_r_down = false;
-        inhibit_r_down = true;
+    if (trigger_inhibit_r) {
+        trigger_inhibit_r = false;
+        inhibit_r = true;
     }
-    if (trigger_inhibit_m_down) {
-        trigger_inhibit_m_down = false;
-        inhibit_m_down = true;
+    if (trigger_inhibit_m) {
+        trigger_inhibit_m = false;
+        inhibit_m = true;
     }
 
     if (df::global::enabler) {
-        if (!df::global::enabler->mouse_lbut)
-            inhibit_l_down = false;
-        if (!df::global::enabler->mouse_rbut)
-            inhibit_r_down = false;
-        if (!df::global::enabler->mouse_mbut)
-            inhibit_m_down = false;
+        if (!df::global::enabler->mouse_lbut_down)
+            inhibit_l = false;
+        if (!df::global::enabler->mouse_rbut_down)
+            inhibit_r = false;
+        if (!df::global::enabler->mouse_mbut_down)
+            inhibit_m = false;
     }
 }
diff --git a/library/lua/gui.lua b/library/lua/gui.lua
index bba7222b9..ba49e0cdc 100644
--- a/library/lua/gui.lua
+++ b/library/lua/gui.lua
@@ -696,16 +696,12 @@ end
 
 DEFAULT_INITIAL_PAUSE = true
 
-local zscreen_inhibit_mouse_l = false
-
 -- ensure underlying DF screens don't also react to handled clicks
 function markMouseClicksHandled(keys)
-    if keys._MOUSE_L_DOWN then
-        -- note we can't clear mouse_lbut here. otherwise we break dragging,
-        df.global.enabler.mouse_lbut_down = 0
-        zscreen_inhibit_mouse_l = true
+    if keys._MOUSE_L then
+        df.global.enabler.mouse_lbut = 0
     end
-    if keys._MOUSE_R_DOWN then
+    if keys._MOUSE_R then
         df.global.enabler.mouse_rbut_down = 0
         df.global.enabler.mouse_rbut = 0
     end
@@ -789,7 +785,7 @@ function ZScreen:onInput(keys)
     local has_mouse = self:isMouseOver()
     if not self:hasFocus() then
         if has_mouse and
-                (keys._MOUSE_L_DOWN or keys._MOUSE_R_DOWN or
+                (keys._MOUSE_L or keys._MOUSE_R or
                  keys.CONTEXT_SCROLL_UP or keys.CONTEXT_SCROLL_DOWN or
                  keys.CONTEXT_SCROLL_PAGEUP or keys.CONTEXT_SCROLL_PAGEDOWN) then
             self:raise()
@@ -804,22 +800,15 @@ function ZScreen:onInput(keys)
         return
     end
 
-    if self.pass_mouse_clicks and keys._MOUSE_L_DOWN and not has_mouse then
+    if self.pass_mouse_clicks and keys._MOUSE_L and not has_mouse then
         self.defocused = self.defocusable
         self:sendInputToParent(keys)
         return
-    elseif keys.LEAVESCREEN or keys._MOUSE_R_DOWN then
+    elseif keys.LEAVESCREEN or keys._MOUSE_R then
         self:dismiss()
         markMouseClicksHandled(keys)
         return
     else
-        if zscreen_inhibit_mouse_l then
-            if keys._MOUSE_L then
-                return
-            else
-                zscreen_inhibit_mouse_l = false
-            end
-        end
         local passit = self.pass_pause and keys.D_PAUSE
         if not passit and self.pass_mouse_clicks then
             if keys.CONTEXT_SCROLL_UP or keys.CONTEXT_SCROLL_DOWN or
diff --git a/library/lua/gui/dialogs.lua b/library/lua/gui/dialogs.lua
index 499fa6305..95a56d0c4 100644
--- a/library/lua/gui/dialogs.lua
+++ b/library/lua/gui/dialogs.lua
@@ -57,11 +57,11 @@ function MessageBox:onDestroy()
 end
 
 function MessageBox:onInput(keys)
-    if keys.SELECT or keys.LEAVESCREEN or keys._MOUSE_R_DOWN then
+    if keys.SELECT or keys.LEAVESCREEN or keys._MOUSE_R then
         self:dismiss()
         if keys.SELECT and self.on_accept then
             self.on_accept()
-        elseif (keys.LEAVESCREEN or keys._MOUSE_R_DOWN) and self.on_cancel then
+        elseif (keys.LEAVESCREEN or keys._MOUSE_R) and self.on_cancel then
             self.on_cancel()
         end
         gui.markMouseClicksHandled(keys)
@@ -129,7 +129,7 @@ function InputBox:onInput(keys)
             self.on_input(self.subviews.edit.text)
         end
         return true
-    elseif keys.LEAVESCREEN or keys._MOUSE_R_DOWN then
+    elseif keys.LEAVESCREEN or keys._MOUSE_R then
         self:dismiss()
         if self.on_cancel then
             self.on_cancel()
@@ -231,7 +231,7 @@ function ListBox:getWantedFrameSize()
 end
 
 function ListBox:onInput(keys)
-    if keys.LEAVESCREEN or keys._MOUSE_R_DOWN then
+    if keys.LEAVESCREEN or keys._MOUSE_R then
         self:dismiss()
         if self.on_cancel then
             self.on_cancel()
diff --git a/library/lua/gui/widgets.lua b/library/lua/gui/widgets.lua
index 6a0a0091b..05d237f35 100644
--- a/library/lua/gui/widgets.lua
+++ b/library/lua/gui/widgets.lua
@@ -273,7 +273,7 @@ end
 
 function Panel:onInput(keys)
     if self.kbd_get_pos then
-        if keys.SELECT or keys.LEAVESCREEN or keys._MOUSE_R_DOWN then
+        if keys.SELECT or keys.LEAVESCREEN or keys._MOUSE_R then
             Panel_end_drag(self, not keys.SELECT and self.saved_frame or nil,
                            not not keys.SELECT)
             return true
@@ -281,7 +281,6 @@ function Panel:onInput(keys)
         for code in pairs(keys) do
             local dx, dy = guidm.get_movement_delta(code, 1, 10)
             if dx then
-                local frame_rect = self.frame_rect
                 local kbd_pos = self.kbd_get_pos()
                 kbd_pos.x = kbd_pos.x + dx
                 kbd_pos.y = kbd_pos.y + dy
@@ -292,9 +291,9 @@ function Panel:onInput(keys)
         return
     end
     if self.drag_offset then
-        if keys._MOUSE_R_DOWN then
+        if keys._MOUSE_R then
             Panel_end_drag(self, self.saved_frame)
-        elseif keys._MOUSE_L then
+        elseif keys._MOUSE_L_DOWN then
             Panel_update_frame(self, Panel_make_frame(self))
         end
         return true
@@ -302,7 +301,7 @@ function Panel:onInput(keys)
     if Panel.super.onInput(self, keys) then
         return true
     end
-    if not keys._MOUSE_L_DOWN then return end
+    if not keys._MOUSE_L then return end
     local x,y = self:getMouseFramePos()
     if not x then return end
 
@@ -489,7 +488,7 @@ function Panel:onRenderFrame(dc, rect)
         dc:seek(pos.x, pos.y):pen(pen):char(string.char(0xDB))
     end
     if self.drag_offset and not self.kbd_get_pos
-            and df.global.enabler.mouse_lbut == 0 then
+            and df.global.enabler.mouse_lbut_down == 0 then
         Panel_end_drag(self, nil, true)
     end
 end
@@ -718,7 +717,7 @@ function EditField:onInput(keys)
         end
     end
 
-    if self.key and (keys.LEAVESCREEN or keys._MOUSE_R_DOWN) then
+    if self.key and (keys.LEAVESCREEN or keys._MOUSE_R) then
         self:setText(self.saved_text)
         self:setFocus(false)
         return true
@@ -740,8 +739,8 @@ function EditField:onInput(keys)
             end
         end
         return not not self.key
-    elseif keys._MOUSE_L then
-        local mouse_x, mouse_y = self:getMousePos()
+    elseif keys._MOUSE_L_DOWN then
+        local mouse_x = self:getMousePos()
         if mouse_x then
             self:setCursor(self.start_pos + mouse_x - (self.text_offset or 0))
             return true
@@ -986,7 +985,7 @@ function Scrollbar:onRenderBody(dc)
     if self.is_dragging then
         scrollbar_do_drag(self)
     end
-    if df.global.enabler.mouse_lbut == 0 then
+    if df.global.enabler.mouse_lbut_down == 0 then
         self.last_scroll_ms = 0
         self.is_dragging = false
         self.scroll_spec = nil
@@ -1023,7 +1022,7 @@ function Scrollbar:onInput(keys)
             return true
         end
     end
-    if not keys._MOUSE_L_DOWN then return false end
+    if not keys._MOUSE_L then return false end
     local _,y = self:getMousePos()
     if not y then return false end
     local scroll_spec = nil
@@ -1386,11 +1385,11 @@ function Label:onInput(keys)
     if self:inputToSubviews(keys) then
         return true
     end
-    if keys._MOUSE_L_DOWN and self:getMousePos() and self.on_click then
+    if keys._MOUSE_L and self:getMousePos() and self.on_click then
         self.on_click()
         return true
     end
-    if keys._MOUSE_R_DOWN and self:getMousePos() and self.on_rclick then
+    if keys._MOUSE_R and self:getMousePos() and self.on_rclick then
         self.on_rclick()
         return true
     end
@@ -1498,7 +1497,7 @@ end
 function HotkeyLabel:onInput(keys)
     if HotkeyLabel.super.onInput(self, keys) then
         return true
-    elseif keys._MOUSE_L_DOWN and self:getMousePos() and self.on_activate
+    elseif keys._MOUSE_L and self:getMousePos() and self.on_activate
             and not is_disabled(self) then
         self.on_activate()
         return true
@@ -1658,7 +1657,7 @@ end
 function CycleHotkeyLabel:onInput(keys)
     if CycleHotkeyLabel.super.onInput(self, keys) then
         return true
-    elseif keys._MOUSE_L_DOWN and self:getMousePos() and not is_disabled(self) then
+    elseif keys._MOUSE_L and self:getMousePos() and not is_disabled(self) then
         self:cycle()
         return true
     end
@@ -1962,7 +1961,7 @@ function List:onInput(keys)
         return self:submit()
     elseif keys.CUSTOM_SHIFT_ENTER then
         return self:submit2()
-    elseif keys._MOUSE_L_DOWN then
+    elseif keys._MOUSE_L then
         local idx = self:getIdxUnderMouse()
         if idx then
             local now_ms = dfhack.getTickCount()
@@ -2317,7 +2316,7 @@ end
 
 function Tab:onInput(keys)
     if Tab.super.onInput(self, keys) then return true end
-    if keys._MOUSE_L_DOWN and self:getMousePos() then
+    if keys._MOUSE_L and self:getMousePos() then
         self.on_select(self.id)
         return true
     end
@@ -2419,7 +2418,7 @@ local function rangeslider_get_width_per_idx(self)
 end
 
 function RangeSlider:onInput(keys)
-    if not keys._MOUSE_L_DOWN then return false end
+    if not keys._MOUSE_L then return false end
     local x = self:getMousePos()
     if not x then return false end
     local left_idx, right_idx = self.get_left_idx_fn(), self.get_right_idx_fn()
@@ -2527,7 +2526,7 @@ function RangeSlider:onRenderBody(dc, rect)
     if self.is_dragging_target then
         rangeslider_do_drag(self, width_per_idx)
     end
-    if df.global.enabler.mouse_lbut == 0 then
+    if df.global.enabler.mouse_lbut_down == 0 then
         self.is_dragging_target = nil
         self.is_dragging_idx = nil
     end
diff --git a/library/modules/Screen.cpp b/library/modules/Screen.cpp
index 5f98c40e5..a5b347493 100644
--- a/library/modules/Screen.cpp
+++ b/library/modules/Screen.cpp
@@ -1004,6 +1004,8 @@ dfhack_lua_viewscreen::~dfhack_lua_viewscreen()
 
 void dfhack_lua_viewscreen::render()
 {
+    using df::global::enabler;
+
     if (Screen::isDismissed(this))
     {
         if (parent)
@@ -1011,6 +1013,14 @@ void dfhack_lua_viewscreen::render()
         return;
     }
 
+    if (enabler &&
+        (enabler->mouse_lbut_down || enabler->mouse_rbut_down || enabler->mouse_mbut_down))
+    {
+        // synthesize feed events for held mouse buttons
+        std::set<df::interface_key> keys;
+        feed(&keys);
+    }
+
     dfhack_viewscreen::render();
 
     safe_call_lua(do_render, 0, 0);
diff --git a/plugins/lua/buildingplan/inspectoroverlay.lua b/plugins/lua/buildingplan/inspectoroverlay.lua
index 1fcf19028..3c6f0ed5e 100644
--- a/plugins/lua/buildingplan/inspectoroverlay.lua
+++ b/plugins/lua/buildingplan/inspectoroverlay.lua
@@ -127,9 +127,9 @@ function InspectorOverlay:onInput(keys)
     if not require('plugins.buildingplan').isPlannedBuilding(dfhack.gui.getSelectedBuilding(true)) then
         return false
     end
-    if keys._MOUSE_L_DOWN and mouse_is_over_resume_button(self.frame_parent_rect) then
+    if keys._MOUSE_L and mouse_is_over_resume_button(self.frame_parent_rect) then
         return true
-    elseif keys._MOUSE_L_DOWN or keys._MOUSE_R_DOWN or keys.LEAVESCREEN then
+    elseif keys._MOUSE_L or keys._MOUSE_R or keys.LEAVESCREEN then
         self:reset()
     end
     return InspectorOverlay.super.onInput(self, keys)
diff --git a/plugins/lua/buildingplan/itemselection.lua b/plugins/lua/buildingplan/itemselection.lua
index 84e866502..9dfd0cc69 100644
--- a/plugins/lua/buildingplan/itemselection.lua
+++ b/plugins/lua/buildingplan/itemselection.lua
@@ -366,10 +366,10 @@ function ItemSelection:submit(choices)
 end
 
 function ItemSelection:onInput(keys)
-    if keys.LEAVESCREEN or keys._MOUSE_R_DOWN then
+    if keys.LEAVESCREEN or keys._MOUSE_R then
         self.on_cancel()
         return true
-    elseif keys._MOUSE_L_DOWN then
+    elseif keys._MOUSE_L then
         local list = self.subviews.flist.list
         local idx = list:getIdxUnderMouse()
         if idx then
diff --git a/plugins/lua/buildingplan/planneroverlay.lua b/plugins/lua/buildingplan/planneroverlay.lua
index ebd8e6e02..2cc15dfde 100644
--- a/plugins/lua/buildingplan/planneroverlay.lua
+++ b/plugins/lua/buildingplan/planneroverlay.lua
@@ -272,7 +272,7 @@ function ItemLine:reset()
 end
 
 function ItemLine:onInput(keys)
-    if keys._MOUSE_L_DOWN and self:getMousePos() then
+    if keys._MOUSE_L and self:getMousePos() then
         self.on_select(self.idx)
     end
     return ItemLine.super.onInput(self, keys)
@@ -739,7 +739,7 @@ end
 
 function PlannerOverlay:onInput(keys)
     if not is_plannable() then return false end
-    if keys.LEAVESCREEN or keys._MOUSE_R_DOWN then
+    if keys.LEAVESCREEN or keys._MOUSE_R then
         if uibs.selection_pos:isValid() then
             uibs.selection_pos:clear()
             return true
@@ -758,7 +758,7 @@ function PlannerOverlay:onInput(keys)
         return true
     end
     if self:is_minimized() then return false end
-    if keys._MOUSE_L_DOWN then
+    if keys._MOUSE_L then
         if is_over_options_panel() then return false end
         local detect_rect = copyall(self.frame_rect)
         detect_rect.height = self.subviews.main.frame_rect.height +
@@ -828,7 +828,7 @@ function PlannerOverlay:onInput(keys)
             end
        end
    end
-   return keys._MOUSE_L or keys.SELECT
+   return keys._MOUSE_L_DOWN or keys.SELECT
 end
 
 function PlannerOverlay:render(dc)
diff --git a/plugins/lua/hotkeys.lua b/plugins/lua/hotkeys.lua
index 8eff17aae..80f8816e8 100644
--- a/plugins/lua/hotkeys.lua
+++ b/plugins/lua/hotkeys.lua
@@ -269,24 +269,24 @@ function Menu:onSubmit2(_, choice)
 end
 
 function Menu:onInput(keys)
-    if keys.LEAVESCREEN or keys._MOUSE_R_DOWN then
+    if keys.LEAVESCREEN or keys._MOUSE_R then
         return false
     elseif keys.KEYBOARD_CURSOR_RIGHT then
         self:onSubmit2(self.subviews.list:getSelected())
         return true
-    elseif keys._MOUSE_L_DOWN then
+    elseif keys._MOUSE_L then
         local list = self.subviews.list
         local x = list:getMousePos()
         if x == 0 then -- clicked on icon
             self:onSubmit2(list:getSelected())
-            df.global.enabler.mouse_lbut = 0
+            gui.markMouseClicksHandled(keys)
             return true
         end
         if not self:getMouseFramePos() then
             self.parent_view:dismiss()
             return true
         end
-        df.global.enabler.mouse_lbut = 0
+        gui.markMouseClicksHandled(keys)
     end
     self:inputToSubviews(keys)
     return true -- we're modal
diff --git a/plugins/lua/overlay.lua b/plugins/lua/overlay.lua
index d3f0b9c9d..cd5286d0d 100644
--- a/plugins/lua/overlay.lua
+++ b/plugins/lua/overlay.lua
@@ -507,9 +507,6 @@ function feed_viewscreen_widgets(vs_name, vs, keys)
         return false
     end
     gui.markMouseClicksHandled(keys)
-    if keys._MOUSE_L_DOWN then
-        df.global.enabler.mouse_lbut = 0
-    end
     return true
 end
 
diff --git a/plugins/lua/sort.lua b/plugins/lua/sort.lua
index 778bc87b9..6d8c8a298 100644
--- a/plugins/lua/sort.lua
+++ b/plugins/lua/sort.lua
@@ -1148,9 +1148,7 @@ function SquadAssignmentOverlay:refresh_list(sort_widget, sort_fn)
 end
 
 function SquadAssignmentOverlay:onInput(keys)
-    if keys._MOUSE_R_DOWN or
-        keys._MOUSE_L_DOWN and not self:getMouseFramePos()
-    then
+    if keys._MOUSE_R or (keys._MOUSE_L and not self:getMouseFramePos()) then
         -- if any click is made outside of our window, we may need to refresh our list
         self.dirty = true
     end
diff --git a/plugins/lua/zone.lua b/plugins/lua/zone.lua
index 3c07b609f..13182cef1 100644
--- a/plugins/lua/zone.lua
+++ b/plugins/lua/zone.lua
@@ -801,10 +801,12 @@ end
 function AssignAnimalScreen:onInput(keys)
     local handled = AssignAnimalScreen.super.onInput(self, keys)
     if not self.is_valid_ui_state() then
-        view:dismiss()
+        if view then
+            view:dismiss()
+        end
         return
     end
-    if keys._MOUSE_L_DOWN then
+    if keys._MOUSE_L then
         -- if any click is made outside of our window, we need to recheck unit properties
         local window = self.subviews[1]
         if not window:getMouseFramePos() then
@@ -818,7 +820,7 @@ function AssignAnimalScreen:onInput(keys)
 end
 
 function AssignAnimalScreen:onRenderFrame()
-    if not self.is_valid_ui_state() then
+    if view and not self.is_valid_ui_state() then
         view:dismiss()
     end
 end
@@ -1072,6 +1074,7 @@ function CageChainOverlay:init()
             frame={t=0, l=0, r=0, h=1},
             label='DFHack assign',
             key='CUSTOM_CTRL_T',
+            visible=is_valid_building,
             on_activate=function() view = view and view:raise() or show_cage_chain_screen() end,
         },
     }
diff --git a/test/library/gui/widgets.EditField.lua b/test/library/gui/widgets.EditField.lua
index 88625a7bf..8418b67d4 100644
--- a/test/library/gui/widgets.EditField.lua
+++ b/test/library/gui/widgets.EditField.lua
@@ -42,17 +42,17 @@ function test.editfield_click()
     expect.eq(5, e.cursor)
 
     mock.patch(e, 'getMousePos', mock.func(0), function()
-            e:onInput{_MOUSE_L=true}
+            e:onInput{_MOUSE_L_DOWN=true}
             expect.eq(1, e.cursor)
         end)
 
     mock.patch(e, 'getMousePos', mock.func(20), function()
-            e:onInput{_MOUSE_L=true}
+            e:onInput{_MOUSE_L_DOWN=true}
             expect.eq(5, e.cursor, 'should only seek to end of text')
         end)
 
     mock.patch(e, 'getMousePos', mock.func(2), function()
-            e:onInput{_MOUSE_L=true}
+            e:onInput{_MOUSE_L_DOWN=true}
             expect.eq(3, e.cursor)
         end)
 end
diff --git a/test/library/gui/widgets.Scrollbar.lua b/test/library/gui/widgets.Scrollbar.lua
index 548792b3d..dd490256c 100644
--- a/test/library/gui/widgets.Scrollbar.lua
+++ b/test/library/gui/widgets.Scrollbar.lua
@@ -59,37 +59,37 @@ function test.onInput()
     s:update(23, 10, 50)
 
     expect.false_(s:onInput{}, 'no mouse down')
-    expect.false_(s:onInput{_MOUSE_L_DOWN=true}, 'no y coord')
+    expect.false_(s:onInput{_MOUSE_L=true}, 'no y coord')
 
     spec, y = nil, 0
-    expect.true_(s:onInput{_MOUSE_L_DOWN=true})
+    expect.true_(s:onInput{_MOUSE_L=true})
     expect.eq('up_small', spec, 'on up arrow')
 
     spec, y = nil, 1
-    expect.true_(s:onInput{_MOUSE_L_DOWN=true})
+    expect.true_(s:onInput{_MOUSE_L=true})
     expect.eq('up_large', spec, 'on body above bar')
 
     spec, y = nil, 44
-    expect.true_(s:onInput{_MOUSE_L_DOWN=true})
+    expect.true_(s:onInput{_MOUSE_L=true})
     expect.eq('up_large', spec, 'on body just above bar')
 
     spec, y = nil, 45
-    expect.true_(s:onInput{_MOUSE_L_DOWN=true})
+    expect.true_(s:onInput{_MOUSE_L=true})
     expect.nil_(spec, 'on top of bar')
 
     spec, y = nil, 63
-    expect.true_(s:onInput{_MOUSE_L_DOWN=true})
+    expect.true_(s:onInput{_MOUSE_L=true})
     expect.nil_(spec, 'on bottom of bar')
 
     spec, y = nil, 64
-    expect.true_(s:onInput{_MOUSE_L_DOWN=true})
+    expect.true_(s:onInput{_MOUSE_L=true})
     expect.eq('down_large', spec, 'on body just below bar')
 
     spec, y = nil, 98
-    expect.true_(s:onInput{_MOUSE_L_DOWN=true})
+    expect.true_(s:onInput{_MOUSE_L=true})
     expect.eq('down_large', spec, 'on body below bar')
 
     spec, y = nil, 99
-    expect.true_(s:onInput{_MOUSE_L_DOWN=true})
+    expect.true_(s:onInput{_MOUSE_L=true})
     expect.eq('down_small', spec, 'on down arrow')
 end
diff --git a/test/library/gui/widgets.lua b/test/library/gui/widgets.lua
index 88d3ac952..b37fbe04d 100644
--- a/test/library/gui/widgets.lua
+++ b/test/library/gui/widgets.lua
@@ -7,7 +7,7 @@ function test.hotkeylabel_click()
     local l = widgets.HotkeyLabel{key='SELECT', on_activate=func}
 
     mock.patch(l, 'getMousePos', mock.func(0), function()
-            l:onInput{_MOUSE_L_DOWN=true}
+            l:onInput{_MOUSE_L=true}
             expect.eq(1, func.call_count)
         end)
 end
@@ -33,7 +33,7 @@ function test.togglehotkeylabel_click()
     local l = widgets.ToggleHotkeyLabel{}
     expect.true_(l:getOptionValue())
     mock.patch(l, 'getMousePos', mock.func(0), function()
-            l:onInput{_MOUSE_L_DOWN=true}
+            l:onInput{_MOUSE_L=true}
             expect.false_(l:getOptionValue())
         end)
 end