hello lalalei2001, there's an entry named browser.tabs.animate in about:config, you can toggle it to false by double-clicking it but as far as í can see it only disables the animation during opening or closing a tab at the moment (not when you drag it though). there is a open bug for it that asks for the setting to be expanded to the drag animation, but i don't know how likely it is to get fixed soon...

Thanks ^^; I don't mind the opening or closing animation, but the dragging one is a pain.

I Found a working solution: Install the Tab Utilities extension for Firefox and make sure extensions.tabutils.disableTabMoveAnimation is set to true. The animation should now be gone and the lovely arrow back!

I tried the about:config "fix" listed everywhere. The idiotic animation is still there.