Open Thunar in a small window which is not full screen. Type some text to activate the search widget and click the button in the right top window corner to make the window fill the whole screen. Now the search widget is misplaced. When resizing the window via the window borders then the search widget will disappear which is fine I think. This is also the case when moving the whole window with drag and drop with the title bar of the window. Tested with Exo 0.12.4 and Thunar 1.8.1.
Related to Bug #14994 ... moving to the correct package I can reproduce the bug with exo 0.12.4
This happens with detailed list view too. The bug is present in Nemo and Caja also.
Sean Davis referenced this bugreport in commit eb89d98e15cd785f1f6f3dd9c58dec58cde93099 Hide search widget when doing a fullscreen resize (bug #15106) https://git.xfce.org/xfce/exo/commit?id=eb89d98e15cd785f1f6f3dd9c58dec58cde93099
The above patch makes a fullscreen resize behave the same as other resizing: Any resize will make the search widget disappear.
This fix caused a regression, please see my report at https://bugzilla.xfce.org/show_bug.cgi?id=16191.
Reopened with the previous commit.
The general problem seems to be that clicking on the window decoration (including the window buttons) does not create some sort of focus-out event. I assume that a proper fix may not be easy to write, so I suggest to close this report as won't fix.
*** This bug has been marked as a duplicate of bug 15069 ***