If _size_menu was non-null, we just return it. Ergo, it was already null when we reached
this line, which makes calling delete on it completely pointless
This test was added because of confusion about when/where dynamically constructed menus
were constructed and deleted. This should be consistent now, and this additional check
(on top of _size_menu itself being null) should be unnecessary
The manu is rebuilt every time it is required, no need to delete it. In addition, deleting it
in the middle of an event handler causes memory corruption because the entire menu (with all
items and submenus) is deleted before event handling for the menu is completed
Stop the engine if it was started for latency measurement
but measurement was aborted.
Previously the engine was kept running and the "Start' button
was not available.
If this happened during initial session loading, a user
would have to manually restart the engine to proceed.
When the screen-height is insufficient, the loudness-graph is
not included in the dialog. It is still visible in the image
saved with the export (save-export-analysis-image).
For tiny screens the conformity analysis may also be skipped.
```
gtk2_ardour/ardour_ui.cc:2060: error: ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second:
/usr/include/architecture/i386/math.h:343: note: candidate 1: double pow(double, double)
/usr/include/c++/4.2.1/cmath:357: note: candidate 2: float std::pow(float, float)
```
Previously x-axis threshold was in samples. This is
useless unless zoomed in to the max. So in most cases
the first-move was always in x-direction, making constrained
y-axis drags near impossible.
Furthermore the threshold for copy-drags was increased
as per #8686
Region positions were updated in the GUI, before the playlist
was catching up.
The butler thread reads a region using the region's new position,
but the playlist's old range.
Thread 1 (GUI)
```
#22 ARDOUR::Playlist::notify_layering_changed()
#26 ARDOUR::AudioPlaylist::region_changed
#27 ARDOUR::Playlist::region_changed_proxy
#35 ARDOUR::Region::send_change
#36 ARDOUR::Region::set_position
#37 RegionRippleDrag::remove_unselected_from_views
#38 RegionRippleDrag::finished
```
LayeringChanged() also triggers DiskIOProcessor::playlist_modified
which schedules a pending-override and summons the butler.
Note that when moving only a few regions the butler starts after all
updates have been completed.
Butler thread:
```
#4 ARDOUR::AudioRegion::read_at
#5 ARDOUR::AudioPlaylist::read
#6 ARDOUR::DiskReader::audio_read
#7 ARDOUR::DiskReader::overwrite_existing_audio
#8 ARDOUR::DiskReader::overwrite_existing_buffers
#9 ARDOUR::Track::overwrite_existing_buffers
#10 ARDOUR::Session::non_realtime_overwrite
```
Region read fails:
```
libs/ardour/audioregion.cc:503 assert (position >= _position);
(gdb) p position
$1 = 1312000
(gdb) p _position
$2 = {<PBD::PropertyTemplate<long>> = {_have_old = true,
_current = 1336000, _old = 1312000} }
```
The DraggingView's time_axis_view (index) is set to the size of _time_axis_views
in ::motion() near line 1149. This makes it invalid as index into the vector.