x11: Popup positions after constraining are in the window-relative space, not global

(cherry picked from commit 210b317d8dc638407505390a032a11c54b48d789)

src/video/x11/SDL_x11window.c

@@ -1438,7 +1438,6 @@ void X11_ShowWindow(SDL_VideoDevice *_this, SDL_Window *window)
     SDL_WindowData *data = window->internal;
     Display *display = data->videodata->display;
     bool bActivate = SDL_GetHintBoolean(SDL_HINT_WINDOW_ACTIVATE_WHEN_SHOWN, true);
-    bool position_is_absolute = false;
     bool set_position = false;
     XEvent event;
 
@@ -1446,9 +1445,6 @@ void X11_ShowWindow(SDL_VideoDevice *_this, SDL_Window *window)
         // Update the position in case the parent moved while we were hidden
         X11_ConstrainPopup(window, true);
         data->pending_position = true;
-
-        // Coordinates after X11_ConstrainPopup() are already in the global space.
-        position_is_absolute = true;
         set_position = true;
     }
 
@@ -1491,14 +1487,11 @@ void X11_ShowWindow(SDL_VideoDevice *_this, SDL_Window *window)
         const int tx = data->pending_position ? window->pending.x : window->x;
         const int ty = data->pending_position ? window->pending.y : window->y;
         int x, y;
-        if (position_is_absolute) {
-            x = tx;
-            y = ty;
-        } else {
-            SDL_RelativeToGlobalForWindow(window,
-                                          tx - data->border_left, ty - data->border_top,
-                                          &x, &y);
-        }
+
+        SDL_RelativeToGlobalForWindow(window,
+                                      tx - data->border_left, ty - data->border_top,
+                                      &x, &y);
+
         data->pending_position = false;
         X11_XMoveWindow(display, data->xwindow, x, y);
     }