Avoid flashes of bad bg on pane resize

Author: pfrazee

app/fg/shell-window/panes.js

@@ -100,20 +100,23 @@ class ShellWindowPanes extends LitElement {
     e.preventDefault()
     e.stopPropagation()
     this.isResizing = true
+    this.requestUpdate()
     bg.views.setPaneResizeModeEnabled(true, pane.id, edge)
   }
 
   onMouseMove (e) {
     if (this.isResizing && !e.buttons) {
       bg.views.setPaneResizeModeEnabled(false)
       this.isResizing = false
+      this.requestUpdate()
     }
   }
 
   onMouseUp (e) {
     if (this.isResizing) {
       bg.views.setPaneResizeModeEnabled(false)
       this.isResizing = false
+      this.requestUpdate()
     }
   }
 }