Revert "consolidate full refresh logic in widgets.Panel"

This reverts commit 33787473f0.

I've already found another use case where we need a more general
implementation -- modal dialogs that inherit from FramedScreen that
appear and disappear

docs/dev/Lua API.rst

@@ -2366,6 +2366,12 @@ Supported callbacks and fields are:
   In order to make a dialog where portions of the parent viewscreen are still
   visible in the background, call ``screen:renderParent()``.
 
+  If artifacts are left on the parent even after this function is called, such
+  as when the window is dragged or is resized, any code can set
+  ``gui.Screen.request_full_screen_refresh`` to ``true``. Then when
+  ``screen.renderParent()`` is next called, it will do a full flush of the
+  graphics and clear the screen of artifacts.
+
 * ``function screen:onIdle()``
 
   Called every frame when the screen is on top of the stack.

library/lua/gui.lua

@@ -597,6 +597,7 @@ end
 Screen = defclass(Screen, View)
 
 Screen.text_input_mode = false
+Screen.request_full_screen_refresh = false
 
 function Screen:postinit()
     self:onResize(dscreen.getWindowSize())
@@ -622,6 +623,10 @@ function Screen:renderParent()
     else
         dscreen.clear()
     end
+    if Screen.request_full_screen_refresh then
+        df.global.gps.force_full_display_count = 1
+        Screen.request_full_screen_refresh = false
+    end
 end
 
 function Screen:sendInputToParent(...)

library/lua/gui/widgets.lua

@@ -442,7 +442,7 @@ end
 -- adding gaps between widgets according to self.autoarrange_gap.
 function Panel:postUpdateLayout()
     -- don't leave artifacts behind on the parent screen when we move
-    self.request_full_screen_refresh = true
+    gui.Screen.request_full_screen_refresh = true
 
     if not self.autoarrange_subviews then return end
 
@@ -464,10 +464,6 @@ end
 
 function Panel:onRenderFrame(dc, rect)
     Panel.super.onRenderFrame(self, dc, rect)
-    if self.request_full_screen_refresh then
-        df.global.gps.force_full_display_count = 1
-        self.request_full_screen_refresh = false
-    end
     if not self.frame_style then return end
     gui.paint_frame(dc, rect, self.frame_style, self.frame_title)
     if self.kbd_get_pos then