theres a better work around i think, if you want a simple cross dissolve, go into the motion of the selected clips, and place your next track ontop of the first one, and use opacity key points to more accurately dissolve your clips.
I find it a bit more time consuming, but way less stressful than trying to insert a preset timed cross disolve, then having to deal with the headaches of my clip shifting when i lengthen or shorten the transition.
adobe premire, (god forbid) has a very useful transition track between video tracks 1 and 2, and it does the basic same thing as the opacity overlap idea. Except you have way more control over your transitions because you are not placing them directly onto your footage. While i like final cut way better for darn near everything, i miss the old days of premiere when i have to do something as simple as a stinkinng cross dissolve. (The most common transition known to man, and its a pain in the behind to use in final cut, seems to me, cross dissolves are the heart of editing, and final cut cant get this simplistic feature right.)
I havent tried to deselect the snapping tool, perhaps that would make transitions a lot easier, in the mean time, ill continue to use the motion opacity roundabout for extreamly complex cross dissolves that are less than or more than a second in durration.
There is a way in the preferences menu to adjust the transition default time length but honestly, wouldnt it be quicker to use opacity? (Unless you have to use a page peal, then god help you)