fix(macOS): Improve updating of transparent titlebar tabs backgrounds

FAR from a perfect fix, as the background seen through the tabs during window drags will be behind by a frame or so still, but definitely a vast improvement over not updating at all.

macos/Sources/Features/Terminal/TerminalController.swift

@@ -140,6 +140,18 @@ class TerminalController: NSWindowController, NSWindowDelegate,
         }
     }
     
+    func fixTabBar() {
+        // We do this to make sure that the tab bar will always re-composite. If we don't,
+        // then the it will "drag" pieces of the background with it when a transparent
+        // window is moved around.
+        //
+        // There might be a better way to make the tab bar "un-lazy", but I can't find it.
+        if let window = window, !window.isOpaque {
+            window.isOpaque = true
+            window.isOpaque = false
+        }
+    }
+    
     @objc private func onFrameDidChange(_ notification: NSNotification) {
         // This is a huge hack to set the proper shortcut for tab selection
         // on tab reordering using the mouse. There is no event, delegate, etc.
@@ -335,6 +347,11 @@ class TerminalController: NSWindowController, NSWindowDelegate,
     
     func windowDidBecomeKey(_ notification: Notification) {
         self.relabelTabs()
+        self.fixTabBar()
+    }
+    
+    func windowDidMove(_ notification: Notification) {
+        self.fixTabBar()
     }
     
     // Called when the window will be encoded. We handle the data encoding here in the