diff --git a/library/modules/Gui.cpp b/library/modules/Gui.cpp
index f9e15aac4..56aa09b7f 100644
--- a/library/modules/Gui.cpp
+++ b/library/modules/Gui.cpp
@@ -1836,6 +1836,12 @@ df::coord Gui::getMousePos()
 {
     df::coord pos;
     if (gps && gps->mouse_x > -1) {
+        // return invalid coords if the cursor is not over the map
+        DwarfmodeDims dims = getDwarfmodeViewDims();
+        if (gps->mouse_x < dims.map_x1 || gps->mouse_x > dims.map_x2 ||
+                gps->mouse_y < dims.map_y1 || gps->mouse_y > dims.map_y2) {
+            return pos;
+        }
         pos = getViewportPos();
         pos.x += gps->mouse_x - 1;
         pos.y += gps->mouse_y - 1;