This question is based on a misunderstanding due to a bug in TeXStudio: There should be a warning when you use a key-combination that has already been used. However, this warning may be absent when for some reason two different parameterizations of the same key are detected. This happens for example for
CTRL+SHIFT+6. Make sure to use the latter form by typing it in by hand (rather than the automatical detection which strangely does not result in the format used by the rest of TeXStudio). (See my answer for more details.)
When I wanted to change some keyboard shortkeys in TeXStudio I ran into some trouble. I started changing some shortcuts to combinations that I liked, hoping/thinking that if I would use a combination that was already in use TeXStudio would warn me what other key already uses that combination. It seems that TeXStudio has no such check leading to problems with combinations that are used multiple times. In addition it seems that TeXStudio has no way to search through the shortcuts by key combinations. Since there are thousands of shortcuts it would take forever to find the doubles. Did I overlook a way to search by key combination? Is there some other solution?
I am interested in finding the actions the key bindings had been bound to by default in order to remove those (not my new ones) so that I can replace them with my own.