[Lazarus] Qt5 build of program, modal dialogs go to background

[AlexeyT]

I made Qt5 build of CudaText, pls test and see is my bug present? I test 
on Ubuntu w/o Qt5:

user at PC:~$ qmake --version
qmake: could not exec '/usr/lib/x86_64-linux-gnu/qt4/bin/qmake': No such 
file or directory
user at PC:~$ qmake-qt5 --version
Command 'qmake-qt5' not found, did you mean:
   command 'qmake-qt4' from deb qt4-qmake (4:4.8.7+dfsg-7ubuntu1)

steps.

- get beta of Qt5 build 
https://sourceforge.net/projects/cudatext/files/beta_version/

- configure Python engine in it: 
https://wiki.freepascal.org/CudaText#Python_on_Linux.2C_BSD.2C_Solaris

- open Plugins / Options Editor dialog, and drag this dialog by it 
caption. Here dialog always jumps to BACK of main cudatext dialog during 
dragging (and it jumps by pixels too). About dialog don't jump.


-- 
Regards,
Alexey