is data available in the clipboard or not. "Copy" and "Select All" now
work.
All position updates are now handled by a separate looper class (UpdateLooper),
and are actually applied at the editor. UpdateLooper will send a kMsgUpdateData
to its target synchronously when necessary. Seeking a file now works nicely
and very smooth.
HeaderView::MessageReceived() and UpdateLooper::MessageReceived() only
consider the most current update message for kMsgSliderUpdate resp.
kMsgPositionUpdate.
git-svn-id: file:///srv/svn/repos/haiku/trunk/current@6707 a95241bf-73f2-0310-859d-f6bbb57e9c96