Hello, i ran into a serious issue while using this module,
i'm pretty confused about what caused this but i'll try to explain:
my problem was that the administration theme was not loaded when it should have been, i mean that going to /admin or any other page where the administration theme would normally be loaded would not cause the theme to switch.

So i've tried to investigate and i came up with the basic loading of a theme in drupal, a theme() call that initializes the theme through the init_theme() function.
I couldn't find lot of documentation about this, but i read some hints about not calling theme() while using hook_init(), for example, to avoid messing the theme system.

I tracked back the init_theme() function and the first call was made by wysiwyg_filter module, inside the wysiwyg_filter_admin file.
The function is wysiwyg_filter_settings_filter($format), at line 39 there's a call to a t() function where a % placeholder is used.
I took a look at common.inc in /includes and i saw that a % placeholder is passed through a theme() function, $args[$key] = theme('placeholder', $value); at line 938

The wysiwyg_filter_settings_filter($format) function is called by the hook_filter implementation by the wysiwyg_filter module, while $op is 'settings', at line 25.

I really don't understand why a theme() call made by an hook_filter() implementation by a plugin would run before hook_init() in system.module, i checked the weight of the wysiwyg.module and it was set to 0, anyway.
what i know for sure is that removing that placeholder fixed my problem, so i guess we need to use a different placeholder, like @ instead of %

I found a similar issue about a different module here

Thanks,
Da.