TextArea looses selection while trying to change text format

Steps to reproduce
1) Compile and run example qtquickcontrols/examples/quick/controls/texteditor
2) Select couple of lines of text.
3) Press on any gui control which can acquire focus (in the example such controls are combobox for font family choosing, black square button for text colour choosing and spinbox for text size), so press, for example, button for selecting text colour.
4) You shall see that text selection vanishes!

So, after you press "Ok" in dialog, selected text will not change colour.

// Yet another (not so important) bug with this example
Run the app
Start selecting text from the beginning ("TextArea")
After you selected several first chars after "TextArea" ("The TextArea control ") you shall see that heading changed its size
It is because 1) you change size of text in spin box according to end of selection 2) then you on sizeChanged apply its size to all selection