Pattern Editor gives no indication when it's not possible to remove additional steps

In the Pattern Editor, there are buttons to remove/add/duplicate steps. When clicked, the latter two always do as their name/icon suggests. However if all patterns are only 1 bar in length, then the "remove steps" button will do nothing.

It seems appropriate that in such conditions, it should be deactivated (no mouse-over action, maybe rendered semi-transparent, etc). This kind of thing is already done with the edit -> undo/redo context options.

This also needs to be done to the "remove steps" context menu option when right-clicking on a pattern (see below).

On a related note, the "paste" option should also be greyed out if there's no valid clipboard data. I think "clear all notes" can remain always-enabled, as it will always do as it says (performing the action on an empty pattern does indeed leave you with all notes cleared, whereas performing the "remove steps" action on a pattern of 1 bar in length does not remove any steps).

Start in the Pattern Editor controls and context menu, comparing their behavior with the existing Edit > undo/redo context options. The remove-steps actions should be visibly unavailable when patterns are only one bar long, and paste should be unavailable without valid clipboard data; clear all notes should remain enabled.