Implements a TextMate like UI for command invocation.
Execute "LUICommandSelection install" to install. Ctrl-/ triggers, esc cancels, use arrow keys/home/end to navigate (no need to move out of the filter field). Filter text will intelligently filter, '/' selects sub structure marker. Return will execute the command.
Requires FixTextFieldMorphLinePosition-M5711-ASB.1.cs.gz, which is attached to Mantis bug #5711.