I've had a very quick look at your first question. I think that you need to tackle the problem in a slightly different way.
The Form doesn't recognise any mousemove or mousedown events when obstructed by controls. It might be better to draw directly on the form.
Have a look at my IconEditor example which can be found here http://www.b4x.com/forum/showthread.php?t=585&page=2 (bottom of second page), its nowhere near finished but might help you with what you are trying to achieve.
I have posted my program on the FSG website 9falling sand game) as an open source so all of these questions have been answered. The program is much more efficiant now. Thanks for the suggestion.