Merge pull request #22355 from dalthviz/fixes_issue_22266

PR: Prevent first time render glitch by calling position logic via a timer in `showEvent` (Menus)

spyder/api/widgets/menus.py

@@ -14,6 +14,7 @@
 
 # Third party imports
 import qstylizer.style
+from qtpy.QtCore import QTimer
 from qtpy.QtGui import QCursor
 from qtpy.QtWidgets import QAction, QMenu, QProxyStyle, QStyle, QWidget
 
@@ -457,10 +458,8 @@ def __str__(self):
     def __repr__(self):
         return f"SpyderMenu('{self.menu_id}')"
 
-    # ---- Qt methods
-    # -------------------------------------------------------------------------
-    def showEvent(self, event):
-        """Adjustments when the menu is shown."""
+    def _adjust_menu_position(self):
+        """Menu position adjustment logic to follow custom style."""
         if not self._is_shown:
             # Reposition submenus vertically due to padding and border
             if self._reposition and self._is_submenu:
@@ -487,7 +486,17 @@ def showEvent(self, event):
 
         self.move(self.pos().x() + delta_x, self.pos().y())
 
-        super().showEvent(event)
+    # ---- Qt methods
+    # -------------------------------------------------------------------------
+    def showEvent(self, event):
+        """Call adjustments when the menu is going to be shown."""
+        # To prevent race conditions which can cause partially showing a menu
+        # (as in spyder-ide/spyder#22266), we use a timer to queue the move
+        # related events after the menu is shown.
+        # For more info you can check:
+        #  * https://forum.qt.io/topic/23381/showevent-not-working/3
+        #  * https://stackoverflow.com/a/49351518
+        QTimer.singleShot(0, self._adjust_menu_position)
 
 
 class PluginMainWidgetOptionsMenu(SpyderMenu):