Mimic midikeyboard button behaviour in a row of textbuttons

I have a couple of textbuttons in a row, side-by-side, and want them to behave just like a midikeyboard component.
I can click one individual button(no problem here), but I also want to be able to keep the mouse button down while moving to a next button, and activate the next buttons that way (again, just like in the midikeyboard component). Now, if I enter a textbutton with the mouse-button down, the button will not fire…
How to implement? what combi of textbutton events/memberfunctions should I be using?

looks like there is a solution here