[VersionControl] Ensure that all created compontents get destroyed
properly.
Destroy wasn't called on all of them.
[SourceEditor] Fix context menu.
[SourceEditor] Fixed leak.
The VAdjustement may not be set at that point - it can point to an
empty default adjustment and adding events to that keeps the source
editor in memory. Subscribing to the Allocated event does the same
thing in that case. Furthermore that fixes a bug where the file
settings may not be loaded correctly.