Determine if adding overflow hidden style to doc body is still required

[dlongley]

See:

web-request-rpc/WebAppWindow.js

Lines 133 to 157 in 2ef168c

	// disable scrolling on body
	const body = document.querySelector('body');
	this._bodyOverflowStyle = body.style.overflow;
	body.style.overflow = 'hidden';
	if(!this._destroyed) {
	this.dialog.show();
	} else if(this.windowControl.show) {
	this.windowControl.show();
	}
	}
	}
	/**
	* Called by the client when it wants to hide UI.
	*/
	hide() {
	if(this.visible) {
	this.visible = false;
	// restore `overflow` style on body
	const body = document.querySelector('body');
	if(this._bodyOverflowStyle) {
	body.style.overflow = this._bodyOverflowStyle;
	} else {
	body.style.overflow = '';
	}

This was added a long time ago -- potentially for browsers that needed a polyfill for HTML dialog. If this is no longer needed due to improvements in modern browsers (e.g., full support for dialog support), it would be good to remove it.

[dlongley]

Other modern improvements that could remove the need for changing the body style could involve using viewport width/height units for the iframe in the dialog.