The situation in the next. There are two Ubuntu 14.04.2 LTS, one at home (delivered instead of Debian), the other at work (installed from scratch). There is a python script that uses wxPython: creating a main window (wx.DEFAULT_FRAME_STYLE | wx.STAY_ON_TOP), then child (wx.RESIZE_BORDER).
House: everything works as expected -- child window without ordering, but resisits. At work: a child window without a title does not resisits (via the menu item via the Alt+RMB-still resisits), with the title of (wx.CAPTION) -- resisits. ￼