A press that only brings the window to the front draws nothing

From the development repository at 62e0967.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/guest.md

@@ -81,7 +81,9 @@ from the palette joins the row and stays there in this browser.  White
 is for painting over.  The four lines to the right of the colours are
 the line widths: 0.4, 0.7, 1.2 and 2.4 mm at ordinary pressure.
 
-If a pen is in use, a hand resting on a touch screen is ignored.
+If a pen is in use, a hand resting on a touch screen is ignored.  A
+click on the page that only brings the browser window to the front, when
+you come back to it from another window, makes no mark.
 
 ### Text