No, on that asp page:

all the buttons shows after 2-3 sec (and then 80-90 objects are being downloaded in the background)

 

But on this php page:

the buttons shows after 10-15 sec, AFTER the 80-90 objects has been downloaded.

And there are the same slow performance when editing this post (and that is a asp page?) 

 

I've tested some other similiar editors (for php server), and they are loading fast (even when my cache setting is "Check for newer version every time page opens!)

There are no similiar problems with this browser on other pages. The cache setting is "Automatic".