cursor in gui editboxes jumps two chars when using left/right

[rofl0r]

Describe the bug
e.g. in the select hard disk file widget, when i edit the proposed start directory, cursor left jumps 2 characters left and right 2 characters right.

To Reproduce
Steps to reproduce the behavior:

1. click the select hard disk file, edit default directory with keyboard

Expected behavior
it should move one character only.

Desktop (please complete the following information):

• OS: Linux