greasemonkey scripts not doing anything at all

This is what I did

In Iceweasel (Firefox) in Linux Debian, I added the greasemonkey add-on. Created some simple scripts, imported some simple scripts but NOTHING happened.

I could see that greasemonkey (GS) was saying that it was running the scripts I expected but nothing happened.

If I run the same code on the console it was fine, but not inside GM.


==== Troubleshooting

I added things like:
GM_log("Hello, GM_log");
console.log("on console");
alert('"Hello World!"');


I opened the browser console (Ctrl+Shift+J) but still nothing.


However I could see something not related with the page or my scripts.
"NS_ERROR_XPC_BAD_OP_ON_WN_PROTO: Illegal operation on WrappedNative prototype object"
and it was coming from a script related with greasemonkey internal scripts (not my scripts).



In synaptic (apt-get) I saw a package related with GS and installed it. No changes.


Searching led me to a bug and not much more, but no workaround nor many people with that problem.


Creating a fresh profile and installing GS again did not produce any change.



==== Solution

In synaptic, selected the iceweasel and greasemonkey packages for re-installation.

Problem fixed.



Hopefully someone with the same problem can find this.