Have you uploaded correctly all the js files?
I'm not sure, that could be the issue though. Can you specify which files to add in the MyBB download?
I suggest to reupload all the /jscripts/ directory.
I see you're using much js (jQuery) in your forum, it can cause collisions. Also, try to use the default template and see if it works.
Okay it work in default so I'm guessing that something is missing inside the theme I created?
Try to disable the plugin for the forum tabs, and to disable all the plugins by going to ACP -> Configuration -> General Config -> Disable all plugins.
If it works it's a plugin, if not then it's a problem of your jQuery. (Have you used the jQuery.noConfolict() method?)
Okay, it work when I disabled all the plugins. Will try to disable the forum tabs.
It's not MyTabs. Should I list the plugins I use?
Fit on Page by -G33K-
Force Postbit Layout by Aries-Belgium
Game Section by Paretje
Google SEO by Andreas Klauer
Hide Links by Yaldaram
Multi Attachments by Jammerx2
MentionMe by Wildcard
My Achievements by MyBB-Plugins.com
My Advertisements by Pirata Nervo
MyAlerts by euantor
CKEditor WYSIWYG editor by AliReza_Tofighi (Not using since I'm using SCEditor)(May be problem?)
MyBot by Jones
MyDownloads by Pirata Nervo
MyFacebook Connect by Shade
MyLast by effone
MySubscriptions by MyBB-Plugins.com
MySupport by MattRogowski
MyTabs by Ethan
MyTwitter Connect by Shade
MyUpdates (Client) by ZLight Software
Naoar Donation by Naoar.com
NewPoints by Pirata Nervo
Show the users that has been online today by CraKter
OUGC Awards by Omar Gonzalez
OUGC Require Prefix by Omar G.
Page Manager by Sebastian Wunderlich
Pending Download by Yaldaram
PluginLibrary by Andreas Klauer
Ranks by Edson Ordaz
Redirect After Activation by Yaldaram
SCEditor WYSIWYG editor by Sam Clarke
Side Bar Threads by Yaldaram
Advanced Spoiler by Novan AB
Thumbs Post Rating by TY Yew
Wiki by Jones
XThreads
Some of these plugins are heavily modified by me but it shouldn't have affected the issue.
Go to ACP>Templates & Styles>Templates>YOUR THEME>Showthread Template>Showthread_quickreply
Find and Remove:
id="quick_reply_form"