Currently there is no reasonable "component" for things like bug #7638 when the problem is in more than one component (or a problem that is not directly related to any particular component).
The database does not currently support more than one component per bug report. It would require a substantial design change to implement this. But I will changed this to a RFE and discuss what would be a good solution. An easy interim solution would be to just add a generic component of some kind for people to choose if there is no component associated with their problem. There would just need to be documentation to let them know what to do.