Tried this after restoring factory settings to hopefully make sure it wasn't to do with something hanging around in my startup.blend - basically the texture panels are being shown in the wrong order.

See the attached image, the influence and custom property panels should be shown last, however sometimes the panels referring to properties specific to that texture type get put down the bottom, which is quite bad.

I tested in alpha 2 and this problem doesn't exist there, it works correctly.

Also tried splitting the default 3D View and making a properties editor (to initialise the space type from scratch) and it's even worse that way - for image texture, all image related panels fall to the bottom of the property editor.

Anyway, this is a nasty usability problem - anything to do with the python auto-registration stuff perhaps?