attached (didn't forgot, the form was not working :p)

Are you possibly running Firefox in Private Browsing mode?

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Appearance
• do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

You can create a new profile to test if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

I am not running Firefox in private mode.

I created a new profile as per your suggestion and still the js files are not getting loaded. I checked the addons tab in the new profile and no one was present.

Do you have any idea of what else to check (i hate chrome).

In the console i got an error, not sure if it is related:

firefox -P 1509864047650 addons.xpi WARN Error parsing extensions state: [Exception... "Component returned failure code: 0x80520012 (NS_ERROR_FILE_NOT_FOUND) [amIAddonManagerStartup.readStartupData]" nsresult: "0x80520012 (NS_ERROR_FILE_NOT_FOUND)" location: "JS frame :: resource://gre/modules/addons/XPIProvider.jsm :: loadExtensionState :: line 1554" data: no] Stack trace: loadExtensionState()@resource://gre/modules/addons/XPIProvider.jsm:1554 < getInstallState()@resource://gre/modules/addons/XPIProvider.jsm:1589 < checkForChanges()@resource://gre/modules/addons/XPIProvider.jsm:3122 < startup()@resource://gre/modules/addons/XPIProvider.jsm:2188 < callProvider()@resource://gre/modules/AddonManager.jsm:269 < _startProvider()@resource://gre/modules/AddonManager.jsm:739 < startup()@resource://gre/modules/AddonManager.jsm:906 < startup()@resource://gre/modules/AddonManager.jsm:3090 < observe()@jar:file:///usr/lib64/firefox/omni.ja!/components/addonManager.js:65 console.error:

 Message: TypeError: str is null
 Stack:
   KeyShortcuts.parseElectronKey@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/debugger/new/debugger.js:37806:8

on@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/debugger/new/debugger.js:37942:23 componentDidMount@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/debugger/new/debugger.js:24286:6 notifyAll@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/shared/vendor/react.js:842:9 close@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/shared/vendor/react.js:14599:5 closeAll@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/shared/vendor/react.js:19101:11 perform@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/shared/vendor/react.js:19048:11 batchedMountComponentIntoNode@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/shared/vendor/react.js:12357:3 perform@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/shared/vendor/react.js:19035:13 batchedUpdates@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/shared/vendor/react.js:10660:7 batchedUpdates@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/shared/vendor/react.js:16668:3 _renderNewRootComponent@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/shared/vendor/react.js:12551:5 _renderSubtreeIntoContainer@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/shared/vendor/react.js:12632:21 render@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/shared/vendor/react.js:12653:12 monkeyPatchRender/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/shared/vendor/react-dom.js:128:14 renderRoot@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/debugger/new/debugger.js:3409:6 bootstrapApp@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/debugger/new/debugger.js:32502:5 onConnect</_ref<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/debugger/new/debugger.js:31465:7 step@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/debugger/new/debugger.js:31491:184 step/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/client/debugger/new/debugger.js:31491:362

Now i believe there is some issue with the official package for linux. I downloaded latest version from official website and the same issue is present there:

Version=56.0.2 BuildID=20171024165158

I also installed firefox for developers latest version and it is working fine in this package.

Version=58.0 BuildID=20171103003834