[doom builder 2] select all sectors with one texture [xpost from incorrect forum channel]

Find and replace might be a viable option here as well. It's F3 by default when you're not in visual mode. Then select "sector flat" and type in the name of the current flat. Put a check on "replace" and type in the name of the flat you want instead.

That will work if you want to replace every instance of FLATX with FLATY. If you have other sections where you do want to keep FLATX, then you can use the "Within current selection" function of "Find and Replace."

In any case, you can at the very least use the "Find" function to see where all you have FLATX.

While in visual mode, use shift+left click on the floor texture to select all adjacent floors with that flat.

This also works for ceilings and walls.

18 minutes ago, Aquila Chrysaetos said:

While in visual mode, use shift+left click on the floor texture to select all adjacent floors with that flat.

This also works for ceilings and walls.

i tried this but it does not select it even though it uses the same texture names to the letter.

Well, I don't recommend use 6-7 years old program without updates. Get doom builder x or gzdoom builder bugfix for newest mapping experience. I think both programs allow mark all textures with shift+left mouse click. 

^^^ What Hak3180 said.  Find and replace (F3) is your friend here. 

Agreed with find and replace. If you have lots of small sectors it can be a huge time saver. Second best, but still decent method would be the map overview when you have floor textures displayed. Worst course of action is using visual mode, it is usually the slowest method when it comes to editing several sectors at once, it is best used for texture alignment.