dhtmlx.sh seems to hang for 40 seconds when firebug is used

Non-technical Questions Docs and Samples
#1

While testing in FireFox (36.0.1) with FireBug (2.0.8) active, the webpage always takes at least 40 seconds to appear. With FireBug disabled, the page appears almost instantly. I put together a minimal page that shows the problem:

TEST

Has anyone else run into this?

-Scott Emrick

#2

Forgot to mention I’m using dhtmlxSuite_v413_pro.
-Scott