Works just fine for me. As for finding, its in the same location as the others. If you can find the others, there is no reason why you can't find showcase.
Step 1. ALWAYS filter the list with the type of listener you are looking for. In this case, I specifically mentioned the 'load_class_controller', so you should have pasted that into the filter box.
Step 2. Find the Addon Name (Showcase) and under that will the the listing of ALL 'load_class_controller' that showcase is extending (7 of them).
Step 3. Look at the description of each one. Most developers clearly state what its for.
Here are the default settings for Showcase (10) , XFMG (10) and XFRM (11). Both Showcase and XFMG are set at 10, so its a matter of the system executing one or the other first, but XFRM will always be after both of those, because it is set at 11.
SHOWCASE
XFMG
XFRM
And as you can see, Showcase is 1st, then XFMG and last XFRM.
Lets change Showcase to 22 (which is a higher number than 11) and see what happens...
By changing the execution order to 22, the New Showcase Items tab is now at the end.