src/vs/workbench/browser/layout.ts/Layout/onFullscreenChanged
class Layout:	private onFullscreenChanged(): void {
		this.state.fullscreen = isFullscreen();

		// Apply as CSS class
		if (this.state.fullscreen) {
			this.container.classList.add(Classes.FULLSCREEN);
		} else {
			this.container.classList.remove(Classes.FULLSCREEN);

			if (this.state.zenMode.transitionedToFullScreen && this.state.zenMode.active) {
				this.toggleZenMode();
			}
		}

		// Change edge snapping accordingly
		this.workbenchGrid.edgeSnapping = this.state.fullscreen;

		// Changing fullscreen state of the window has an impact on custom title bar visibility, so we need to update
		if (getTitleBarStyle(this.configurationService) === 'custom') {
			// Propagate to grid
			this.workbenchGrid.setViewVisible(this.titleBarPartView, this.isVisible(Parts.TITLEBAR_PART));

			this.updateWindowBorder(true);

			this.layout(); // handle title bar when fullscreen changes
		}

		this._onDidChangeFullscreen.fire(this.state.fullscreen);
	}