This might be a bug with QtCreator, which I reported on their bugtracker (I will post a link). 

I use two keyboard layouts, french default (azerty) and french bépo. Qtcreator gets confused about which layout to use for keyboard shortcuts and it breaks at least one of them. 

Steps to Reproduce:

1) Have two keyboard layouts, one azerty, one bépo, with azerty as the default one

2) Setup QtCreator to toggle comments on Ctrl+Shift+/ with the "record" button.

Actual Results:

QtCreator records the shortcut as Ctrl+Shift+H instead of Ctrl+Shift+/. On the bépo layout, H corresponds to the / key on azerty.

Expected Results:

QtCreator should record the shortcut as Ctrl+Shift+/.

Additional Information:

The fact that it is not recorded properly breaks the usability of the shortcut in the following way. Once the shortcut is set improperly, pressing Ctrl+Shift+/ does toggle comments. But pressing again does not toggle back, unless I save the edited file with Ctrl+S first. Then it will uncomment.

Using Ctrl+/ on the numpad works 100% of the time.

My current workaround is removing all keyboard layouts but french azerty.