When switching image selection tabs edits done quickly after change can be lost

Reproduction steps

1. Edit a page
2. Insert an image
3. Click on the url tab
4. Instantaneously type an url (only possible with selenium)

Expected

100% of the time the url is taken into account and the select button is enabled

Actual

From time to time, the previous value (i.e., '') is used instead and the select button is not enabled.