scrubbing with calendar / histogram widget

[Dylan McCall]

I suggest that the calendar / histogram widget be modified to support scrubbing, where the user could click and then drag with the mouse to browse through dates very quickly. Here are some reasons to justify the idea:

 * The calendar / histogram widget currently reacts when the user presses with the mouse, and most widgets like this seem to support some kind of click + drag interaction. (For example, menus).
 * The way the widget interacts with the rest of the interface is reminiscent of a scroll bar, which behaves in the way I suggest.
 * Repeatedly clicking is not ergonomic, but there is presently no other way to scan through events in detail. This would provide one way of doing so.

[Dylan McCall (dylanmccall)]

Linking a branch with this feature fully implemented. It may not merge perfectly since I had to make some changes beyond the event handlers in order to improve efficiency and feel (so there could be some conflict with the latest trunk). If you want me to update it to merge nicely, let me know :)

[Randal Barlow (email-tehk)]

Unfortunately I merged it and it is not going to work with the tool tip code. The mask interfere with eachother. I love the idea and I will look into doing it using the pressed and released mask when I get a chance on my accessibility branch, and merging it into trunk if it works

[Randal Barlow (email-tehk)]

Moved tool tip code into a event box thus solving the conflict

[Dylan McCall (dylanmccall)]

Awesome! Thanks, tehk :)

Yah, the event mask thing is a bit of a hack, but the performance hit from handling all those events can be crazy.