With osx client r4905 mouse cursor focus seems to become confused when there is a single click on an xpra session window overlapping a second xpra session window.
Testing with windows client (0.11.0r4903) against a fedora 19 server (0.11.0r4904) the erratic cursor/focus behavior does not occur.
In the edited logs that I included in #438 (I'll load those logs into this ticket when I get a chance), there is an initial focus on window 55 (first drawn on line 31 of the log, comes into focus line 139), followed by a focus shift to window 82 (first drawn on line 43, comes into initial focus on line 157, I think)... then there follows what I assume are indications of mouse-wheel scrolling events occurring on window 55 (lines 174 on).
That is the 'event'. The logs aren't clear that focus shifted to window 82, from what I can tell, but what I did was to click on 55, then click 82, then click 82 again on a portion of the window which, once 82 'rose' to focus, was now overlapping 55. From then on, I never clicked on window 55 again, nor did I scroll the mouse off of window 82.
From the point of line 157 in the log on, my cursor remained hovering over window 82 ... but the mouse scrolling events all seem to register on the lower window (55) despite the appearance of focus being on window 82.
Testing this with xterms showed that the keystrokes would register on the apparently focused window, but also that clicking on a portion of an 'upper' window (with apparent focus) which was 'above' a window space with a link would trigger the link 'through' the apparent-focus window.