Make ripple and roll edits more discoverable during trimming using tooltips
Submitted by Jeff F.T.
See http://www.pitivi.org/manual/trimming.html for details about the ripple and roll trimming modes.
Self-documenting interfaces are good. When the user hovers with the mouse cursor a clip trimming handle we should show a tooltip over the trimming handle that says something like:
Hold shift to move in sync the right-side clips (ripple edit).
Hold ctrl to trim in sync the adjacent clip (roll edit).
These should appear only when there would be additional clips affected by the respective operation. Once the user did them, they should not appear anymore.
Imported from https://bugzilla.gnome.org/show_bug.cgi?id=673176