Version 1.3 adds the filtering features described in the thread previously, plus some other additions and fixes:

• Clicking on a Furniture-to-Modify item narrows the From-Texture list to only those textures used by the furniture item.
• The From-Texture and To-Texture panels now include an incremental search text box.
• From-Texture and Furniture-to-Modify panels now have a right-mouse menu item to show all respective items.
• Icon drawing on deferred loading has been fixed.

How to deal with inbuilt textures is still not addressed (but I'm thinking about it).

Previous installation and usage instructions posted earlier in this thread still apply.