annotation via right-click: make all tags accessible

[jjacke]

If there are "too many" tags on one hierarchic level, only a part of them (I think according to the order of tag generation) are accessible in the right-click menu. The menu should be scrollable to achieve this. (Btw: Tags are shown in alphabetic order here, which is more helpful than the random order in the Tags section of the Annotate module.)

[danbalogh]

I have found that the right-click menu is scrollable using the cursor keys. Scrolling with the mouse wheel would be more productive, but up and down arrows work as a stopgap solution.