1. /drawfill does the same as the paint bucket tool in paint, ie. if the coordinates you specify are red then all red pixels in that area will be replaced with the colour you specified. Look at /drawrect with the -f switch to draw a solid rectangle.

2. You'd have to code your own selection routine by storing the coordinates and details (font, fontsize, bold?) of the text you draw, and then respond to mouse events and whatnot. Fairly complicated.

3. Well-made scripts (argh amp is a brilliant example) will make it seem like actual windows controls are being used, however when using picture windows you have to draw everything yourself, and if you want the display to change when you receive mouse events then you have to redraw the new effects yourself. Nothing is done for you, it's all custom drawing.