Screen orientation (occasionaly) flipping to portrait when navigating

[SteveFree]

Does anyone have this happen - when moving scene angle using  ctrl+alt plus mouse the screen flips around? How can I stop it happeneing? It's a real pain to get it back - I'm using the firestorm viewer

[SteveFree]

I found the answer - I disabled the hotkeys in graphics options after right clicking on the desktop