While I was debugging https://sourceforge.net/p/lxde/bugs/888/ , I noticed other odd behavior with multiple monitor and "current monitor only" option.
Details:
Now we see that taskbutton shows only one lxterminal window.
Expected result:
lxterminal window on the lxpanel monitor raises up
Actual result:
Firstly one lxterminal window on the other side of lxpanel monitor is iconised,
then the other lxterminal window on the other side of lxpanel monitor is also iconised.
Finally the left one lxterminal window on the same side of lxpanel monitor is
iconised, but from taskbutton only one window iconized can be shown.
Proposal patch here