Fix mousewheel problem with Fl_Text_Editor (issue #879)

When an Fl_Text_Editor ended up under the mouse, it took
mousewheel events for itself, freezing navigation of a
parent's Fl_Scroll.

Patch handles mousewheel events for both up/down and left/right
by checking:

    > If editor has no scrollbar (e.g. no content to scroll to),
      then mousewheel events for that scrollbar are ignored
      so the parent can be navigated.

    > If editor has a scrollbar, it handles wheel events until scroller reaches
      an extreme position (e.g. top or bottom), it starts ignoring wheel events
      so the parent can be navigated.

0 files changed, 0 insertions, 0 deletions