Windows not found on Linux

[dancesWithBugs]

Version: 2.1.0

The X11-related window management code doesn't consider that windows are structured as a tree rather than a list. getWindows() returns the children of the root window, but ignores all grandchildren windows.

This becomes problematic e.g. when searching for a window with a specific title. When the grandchild has a window title, but the parent does not, the current implementation cannot find the requested window.