That one really drives me nuts and makes me want to turn off the suggestions (or using the tab key): Whenevery I type a typename like DWORD or int or whatever and press tab (yes, I format my code while typing), I end up with some suggestion inserted. Usually it is the name of another already existing variable of the same type or something similar. However, it always requires me to delete the suggestion (or undo) and type what I want to type. Either turning off the suggestions here or removing tab completion would be an (existing) solution, neither is acceptable.
I run into this periodically as well, although it would not be as bad if I weren't having problems getting some of our library headers to show up in VAX. For example, we have a type named "UInt32", but it doesn't show in VAX's list (I'm working on figuring this out for a separate report), so when I type "UInt32<tab>" it gets replaced with "UInt32x64" which is a Windows/DirectX/Xbox function somewhere. I'm not sure how to make this work the way I want it to while still letting me partially type what I want and hit "Tab".