Scroll option for all drop down menus

And on a second note: for any drop-down selection that has an index attributed to all entries, this index should be directly adressable. We have layer numbers and can type them in for a drop-down selection. But instead of allowing to type in an exact number, we are only allowed to jump through the first digit. That's just numbing.

This is quite frustrating. On AE (OSX) for example I am able to scroll through the mask selection drop-down in the layer window, but on Windows the same menue is only navigatable trough key input.