[Fix] Webview is not focused after cancelling quick open widget

[shahar-h]

Signed-off-by: Shahar Harari shahar.harari@sap.com

What it does

Fixes the following issue:
When quick open widget is triggered while some webview is focused, cancelling the quick open widget doesn't bring focus back to webview. As a result, when triggering quick open widget again by pressing F1 a new browser tab is opened instead.

Root cause of this issue:
When closing quick open widget by pressing escape or changing focus, focus is set to the previousFocusElement:

theia/packages/monaco/src/browser/monaco-quick-open-service.ts

Lines 235 to 238 in 7a88d28

	onCancel: () => {
	if (this.previousActiveElement instanceof HTMLElement) {
	this.previousActiveElement.focus({ preventScroll: true });
	}

previuosFocusElement is webview main frame(The one with webview class) in case webview was focused before triggering the quick open widget, so it's being focused, but since keydown handler is registered on the inner frame (The one with active-frame id) keydown events will stop work from this point until the inner frame is focused manually:

theia/packages/plugin-ext/src/main/browser/webview/pre/main.js

Line 535 in 7a88d28

newFrame.contentWindow.addEventListener('keydown', handleInnerKeydown);

My solution is register to focus events on main webview node and send focus message to inner frame in this case.

How to test

1. Install GitLens VS Code extension.
2. Open Git Lens welcome page by pressing F1 and choose GitLens: Welcome from the command palette.
3. Focus Git Lens welcome page.
4. Press F1 and then press Esc key or mouse left click outside the quick open widget.
5. Press F1 again - the quick open widget should be opened again. Without the fix a new browser tab will be opened instead.

Before:

After:

Review checklist

• as an author, I have thoroughly tested my changes and carefully followed the review guidelines

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[akosyakov]

nice solution, thank you!