ABP and EHH cause scripts not to open automatically by GM

[darkblue]

I've noticed the following issue:
in a clean FF 29.0.1
install these extensions
Adblock Plus 2.6.1
Element Hiding Helper 1.3, and
Greasemonkey 1.15
Then try to install a userscript, i.e. click on links to .user.js file (in userscripts.org:8080, greasyfork, scripts in GitHub,etc):
scripts open in the browser window instead of in GM

If then you disable both ABP or EHH and restart firefox,
then the scripts open in GM as expected.
(In, instead of both, you only disable one(either) of them, and restart FF, then the problem remains)

This issue in GitHub of Greasemonkey Scripts not opening automatically in GM
Screenshot:

[Gingerbread Man]

Filed https://issues.adblockplus.org/ticket/546

If you have any technical information to add, feel free to post a comment there.