I don't know if this would work, but you could try defining a shortcut using shortcut3 that used no image and covered the lsbox.. Set the shortcut to have no left-click action, and to belch up the popup on a right-click. If you hook shortcut3 to the LsBox it should follow the LSBox around too.. Only problem is I don't know if that would end up interfering with any other buttons in the box or even the dragging (ie, shortcut3 may catch the left click and just do nothing with it, instead of passing it to the lsbox..)

Worth a shot anyway.

You may also want to look into SkinBox or WhiteBox, afaik they're LsBox clones with other features.. I've never used 'em myself though.