To reproduce:

• Go to [Site administration->Plugins->Repositories->Manage repositories] and make Youtube videos and Wikimedia 'Enabled and visible'.
• Create an activity which uses a text editor. (I chose a lesson, but it could be a reply in a forum)
• Click the moodle media button on the text editor and click 'Find or upload a sound, video or applet...'
• Select Wikimedia and then do a search for something.
• Find an image and try to upload it.
• It should come up with an error as this isn't the right place to be uploading images.
• Realise your mistake and click on the 'insert/edit image' button and then click 'Find or upload an image...'
• Wikimedia should already be selected. Do a search for something and either hit enter or click select.
• The file picker should think about it very quickly and then display nothing.