sysregion="1" - draws object even if there is no background bellow it. The object still has to be within the layouts region. Only used if desktop alpha is turned off.
sysregion="0" - default.
sysregion="-1" - As far as I can tell it does the same thing as sysregion="0" but I have yet to try KrypticK2's idea.
sysregion="-2" - Cuts The layouts region based on the given bitmap. Any pixel with an alpha value greater then 0 is used to cut the region. Once again only works if desktop alpha is turned off.
sysregion="and" - Draws a pixel only if its parent group's (or layout's) background image has a pixel (with alpha value greater then 0) in the same exact spot directly bellow the pixel (the image can be moved and it will be updated correctly). This does not require desktop alpha to be off.
Hope that helps