Modal view is always refreshing only by moving the mouse.

[BDisp]

This code really decrease the performance a lot because will force always a refresh even if NeedsDisplay, SubViewNeedsDisplay or LayoutNeeded are false.

Terminal.Gui/Terminal.Gui/Application.cs

Lines 668 to 670 in d40db95

	} else if (Current.SuperView == null && Current?.Modal == true) {
	Refresh ();
	}

The follow test will fail:

	[Fact]
	public void Run_Toplevel_With_Modal_View_Does_Not_Refresh_If_Not_Dirty ()
	{
		Init ();
		var count = 0;
		Dialog d = null;
		var top = Application.Top;
		top.DrawContent += (s, a) => count++;
		var iteration = -1;
		Application.Iteration += (s, a) => {
			iteration++;
			if (iteration == 0) {
				d = new Dialog ();
				d.DrawContent += (s, a) => count++;
				Application.Run (d);
			} else if (iteration < 3) {
				Application.OnMouseEvent (new (new () { X = 0, Y = 0, Flags = MouseFlags.ReportMousePosition }));
				Assert.False (top.NeedsDisplay);
				Assert.False (top.SubViewNeedsDisplay);
				Assert.False (top.LayoutNeeded);
				Assert.False (d.NeedsDisplay);
				Assert.False (d.SubViewNeedsDisplay);
				Assert.False (d.LayoutNeeded);
			} else {
				Application.RequestStop ();
			}
		};
		Application.Run ();
		Application.Shutdown ();
		// 1 - First top load, 1 - Dialog load, 1 - Dialog unload, Total - 3.
		Assert.Equal(3, count);
	}