so, i'm stopping to poluate you script DA page, here is my modded script from the one you have send me thru pastebin.com with the progressive populating tree function.
Many issues fixed in my mod, the most important is the bad handle of timers, especially the one used in the get_pl_tree() that block the script when another WSH panel is running in // and use timers too !
when creating a time, you have to be sure that no instance is still running, so you have to set them thru variable (not done in your script, you directly use "window.SetTimeOut(...)") and in timer function you have to Clear it and i personnaly set it to false for creation check as told.
other important modification, in get_pl_tree, i load items until the panel is filled to quick have a good looking panel, then i only call again get_pl_tree once to load the entire tree remaining. with that, load is faster that your call on timer every k%100 after 50 ms (it takes 12 seconds to fill the whole library on my config, now, it downsize to 2 seconds and panel is filled immediatly
my mod :
pastebin.com/Kb0F1Z9Jmaking a script compare to see immediatly my modification compared to your script.
HTH
keep the good work, it rocks!