I've noticed in Qt 5.5.0 and in Qt Creator 3.4.2 (built on Qt 5.5.0), that Actions attempting to use Ctrl++ are not working. Note that the shortcut works correctly in older versions (for example, Qt Creator 2.7.0 built on Qt 5.0.2).

For example, if I try to increase the font size in QtCreator using Ctrl+, nothing happens. The same is true for the ImageViewer example. (Ctrl+ in the ImageViewer increases the image size, but in 5.5.0, it does not work.)

If I bind increasing the font size to another shortcut in QtCreator (via Tools->Options->Environment->Keyboard), such as Ctrl+Z, it works fine.

I did a little debug by overriding keyPressEvent, and it appears that Ctrl++ is being sucked up earlier in the dispatch, but I am having trouble figuring out exactly where.

I am thinking that this is a bug.