After much confusion, I finally got customUI shortcut icon to work, as per Michael's instructions for the shortcut .js and .htm files.
Pressing the button on the task bar shows 5 shortcuts, (so far, prior to doing any /*! */ edits).

(I used "83 Shortcuts", because 82 is being used with Snapshots.)

(With Moi V4 beta)

- Brian

One of the 5 shortcuts showing had this format: script:/*!Select edges v1.2 */ var gd = moi.geometryDatabase; func.....

After adding a new shortcut key to MoI (V4), close and reopen MoI.

I could not locate the script: script:/*! +TOGGLE CURVES HIDE*/..., in order to test it.