Dialog for "New C++ Class" opens with blinking cursor in the first line edit control, but any typed characters are inserted into the source file if there is an open file.

Steps to reproduce:

• Open or create a project;
• Select and open any source file for editing;
• Press Ctrl-N to open the "New File" dialog and select "C/C+" and "C+ Class";
• In the dialog which opens, notice that the first line edit control has a blinking cursor, indicating that the dialog has the focus;
• Start typing. Nothing is inserted into the dialog edit control, but typed characters are inserted into the source file which is behind the dialog.

Expected behavior:
The dialog should receive the input.

Related bug report:
This appears to be related to QTCREATORBUG-28756?