Explicit modality set when "New..." is selected

The popup that happens for entering a category when "New..." is selected is currently NOT modal, despite line 14 stating "modal=True"

I tested it on Ubuntu, Windows 10 and macOS (Big Sur).  All of them showed the category dialog and you could put in the background and return to the main calendar window, which wouldn't be the correct behavior.

Adding this line before the show command:
self.setWindowModality(qtc.Qt.ApplicationModal)
Makes it so the Category dialog is modal.

Tested on Windows, Ubuntu, and macOS.

Author: bsimmons01

Chapter03/calendar_app.py

@@ -33,6 +33,7 @@ def __init__(self):
             clicked=self.close
             )
         self.layout().addWidget(self.cancel_btn)
+        self.setWindowModality(qtc.Qt.ApplicationModal)
         self.show()
 
     @qtc.pyqtSlot()