Added a setting for whether labels can be created by typing in a label track.
The setting can be changed in either the Tracks menu, or the Tracks category in Preferences.
By default the setting is set to on.
The two commands are "selection to next label" and "selection to previous label".
They have default shortcuts alt+right and alt+left.
A label track does not have to be the focus. If there is a single label track in the project, that it used. If there is more than one label track, then the first label track, if any, starting at the focused track is used.
If the commands are used during playback of the project, playback continues from the new cursor/selection.
The commands provide feedback to screen readers: the name of the label, and position in the form of "i of n".
These are "Moved focused track up/down/to top/to bottom" in keyboard
preferences.
There were prior changes that made any shortcuts for them appear in the track
control drop-down menu, but only after closing Preferences. They still did
not appear after restart of Audacity, although the keystrokes had their effect.
See commit bb7dba2b678735da60b857fa99e963396d5a875f
and commit 7608e9cb521a6d57a030e1339b980c85f6b97227
My change here doesn't permit building with gcc 4.8 any more. It would be nicer to do this during configure, but doing it at all may be enough to demote this bug from P1 status.
I also took the opportunity to modifier the Status Bar indications when in the TrackInfo.
1) We now mention ctrl click can select or deselect track.
2) If there is only one track, we don't now prompt about rearranging tracks, since you can't.
3) If you hover in a label track's VRuler (which is just a spacer so that things line up), you now don't get a message.
Progresses us a little towards closing. Ctrl-Click on waveform now removes track selection status, not just adds it, and we don't flicker on again subsequently when we drag. Ctrl-Click won't remove the last remaining selection (by design). Shift-Click can now reduce us down to one track, rather than the previous behaviour when reducing track selection.
The bug was that when the Equalization effect opens in Graphics mode, the sliders are set to zero, and don't do the right thing. This was caused by my incorrect fix for bug #1346.
Fix is to call UpdateGraphic to set the sliders up. Call to UpdateDraw also added, which includes the appropriate calls to Show, rather than have these in PopulateOrExchange.
