Trash docklet takes too long to display context menu when it contains too many files

[Sadi Yumuşak]

I use plank 0.11.1 under Linux Mint 18.3 Cinnamon (64-bit) which is based on Ubuntu 16.04.
I have no issues with plank at all except this minor one which might perhaps be considered a feature request rather than a bug.

At the present when user right clicks the trash docklet it displays a context menu starting with a short list of files (indented text) under the title "Restore Files" (bold text) followed by commands "Open Trash" and "Empty Trash" (also indented and not bold).
The problem is the time to display that context menu seems too long when trash contains for example several thousand files (probably because of listing/counting all of them and then selecting a limited number to display in the menu).

I think it might be better if plank lists files in the trash ONLY when they are not more than the context menu can take. If there are too many files in the trash it might be better for the user to open it and then select files to restore.

And while at it it might also be a good idea to unindent the last two command commands and use regular text for all those three commands in keeping with other context menus, and for example use italic text for the list of files in trash.