Fix glitches with 'on sprite crosshair' after modifying sprite areas

src/app/ui/editor/tool_loop_impl.cpp

@@ -242,6 +242,13 @@ public:
   }
 
   void updateDirtyArea() override {
+    // This is necessary here so the "on sprite crosshair" is hidden,
+    // we update screen pixels with the new sprite, and then we show
+    // the crosshair saving the updated pixels. It fixes problems with
+    // filled shape tools when we release the button, or paint-bucket
+    // when we press the button.
+    HideBrushPreview hide(m_editor->brushPreview());
+
     m_document->notifySpritePixelsModified(
       m_sprite, m_dirtyArea, m_frame);
   }