Fixed the GTK+ crashes (I think) by making resizes synchronous. Since all control resizes happen on the UI thread anyway, we don't need to dispatch back; just call the resizing functions directly. Windows gets this fix too for consistency (and also because it gets rid of the only asynchronous oddity in the system).

stdwndclass_windows.go

@@ -51,13 +51,10 @@ func stdWndProc(s *sysData) func(hwnd _HWND, uMsg uint32, wParam _WPARAM, lParam
 				if r1 == 0 {
 					panic("GetClientRect failed: " + err.Error())
 				}
-				// run the resize in a goroutine, since the WndProc is being run on uitask
-				go func() {
-					err = s.resize(int(r.Left), int(r.Top), int(r.Right), int(r.Bottom))
-					if err != nil {
-						panic("child resize failed: " + err.Error())
-					}
-				}()
+				err = s.resize(int(r.Left), int(r.Top), int(r.Right), int(r.Bottom))
+				if err != nil {
+					panic("child resize failed: " + err.Error())
+				}
 			}
 			return 0
 		case _WM_CLOSE:

sysdata_unix.go

@@ -48,12 +48,13 @@ var classTypes = [nctypes]*classData{
 				return func() bool {
 					if w.container != nil && w.resize != nil {		// wait for init
 						width, height := gtk_window_get_size(w.widget)
-						// run in another goroutine since this will be called in uitask
-						go func() {
-							w.resize(0, 0, width, height)
-						}()
+						err := w.resize(0, 0, width, height)
+						if err != nil {
+							panic("child resize failed: " + err.Error())
+						}
 					}
 					// returning false indicates that we continue processing events related to configure-event; if we choose not to, then after some controls have been added, the layout fails completely and everything stays in the starting position/size
+					// TODO make sure this is the case
 					return false
 				}
 			},
@@ -198,14 +199,8 @@ func (s *sysData) setText(text string) error {
 }
 
 func (s *sysData) setRect(x int, y int, width int, height int) error {
-	ret := make(chan struct{})
-	defer close(ret)
-	uitask <- func() {
-		gtk_fixed_move(s.container, s.widget, x, y)
-		gtk_widget_set_size_request(s.widget, width, height)
-		ret <- struct{}{}
-	}
-	<-ret
+	gtk_fixed_move(s.container, s.widget, x, y)
+	gtk_widget_set_size_request(s.widget, width, height)
 	return nil
 }
 

sysdata_windows.go

@@ -226,23 +226,15 @@ func (s *sysData) setText(text string) error {
 }
 
 func (s *sysData) setRect(x int, y int, width int, height int) error {
-	ret := make(chan uiret)
-	defer close(ret)
-	uitask <- &uimsg{
-		call:		_moveWindow,
-		p:		[]uintptr{
-			uintptr(s.hwnd),
-			uintptr(x),
-			uintptr(y),
-			uintptr(width),
-			uintptr(height),
-			uintptr(_TRUE),
-		},
-		ret:		ret,
-	}
-	r := <-ret
-	if r.ret == 0 {		// failure
-		return fmt.Errorf("error setting window/control rect: %v", r.err)
+	r1, _, err := _moveWindow.Call(
+		uintptr(s.hwnd),
+		uintptr(x),
+		uintptr(y),
+		uintptr(width),
+		uintptr(height),
+		uintptr(_TRUE))
+	if r1 == 0 {		// failure
+		return fmt.Errorf("error setting window/control rect: %v", err)
 	}
 	return nil
 }