Move GMail messages to Trash when messages are moved to another account in Thunderbird

[dlech]

Message received via email:

Hi there! I previously was setting Thunderbird "when a message is deleted, move it to gmail's Trash folder" but I do like the simplicity of your buttons. However one hassle I've had with thunderbird for years is this and I wonder if your addon (or a new addon) could fix it.

Basically this is what happens:

I run low on gmail space.
I decide to move lots of old large emails to Local Folders instead of keeping them on gmail.
I "move" those emails from gmail to local folders.
Even though I have "when deleted move to gmail->trash" set up, moved emails when "deleted" this doesn't happen to, although it does when pressing delete (talking about normal behavior without your addon)
Result: Inbox/etc tag removed, email still in All Mail, no space saved.

Work around I now use:
Select all the emails to move off of gmail.
RIght click, Copy to local folders
RIght click, Move to gmail->trash.

Feature request:
When moving an email from gmail to a local folder, also copy it to gmail->Trash.
Alternatively, fix the delete step at the end of moving emails so if 'when deleting, copy to X" is chosen it will do this after moving emails, not just clicking Delete key.