i think i've found the "fix"
(this is for adw ex, idk about lp)
when i installed GB, i just restored adw from backup and also restored my settings.
i got the horrible lag of course.
so later, i installed root explorer and proceeded to clean out all the bloat including blur home.
I re-installed adw ex FRESH and did not re-store any settings or saved desktops.
(i did this before i removed blur home fyi)
so i filled up 5 screens and things were nice and smooth.
I added my 2 other screens and proceeded to add a widget and bam.. right back to the lag.
so I rebooted.. things where smooth..
tried to add a widget to the 7th screen and got the lag again.
I rebooted and things were smooth.
so it seems for me, every time i add a widget, i need to reboot and then things are fine.
crappy way to do it, but it seems to be working. once you get your desktop setup the way you want, you can probably just let run until we get a fix for this issue.