P:(Masking) various masks , Amount Slider on Panel

In various masks, if you click on the triangle, the panel changes to showing just an Amount Slider, this Amount slider is not visible in the normal panel. Why is this slider not part of the normal mask panel. This slider, when use, also turns off the overlay, would be better if it did not.

after clciking

I propose a Request for Change:

• Place that amount slider on the top of the normal mask panel. as opposed to having to go thru that step of changing the panel.
• Allow the Overlay of the mask to stay visible when adjusting the Amount Slider as to indicate effect.
• Make it so double clicking on slider moves it back to default currently it does not.

note; I have reset my preferences just to make sure my rig is behaving.

Inquiry, those triangles we click on, what are they called? Stating triangle thingy just does not cut it.