Every time I use the deconstruction planner, I end up with a red square in my inventory. Why?

[THX 1138 4EB]

How do I stop red squares taking up space in my inventory after using the deconstruction planner to get robots to remove some old stuff? Holding shift and right clicking on it moves it to a trash slot but then robots take these garbage squares and use them to take up space in logistics chests.

[Fel]

I don't know how you are using them but there are two main ways to use deconstruction planners depending on what you want from them.

If you want to remove everything in the area, you just click on the deconstruction planner in the toolbar (on the right of the hotbar), select the area and hit the key that frees your hands (Q by default), it shouldn't go to your inventory that way.

If you want to remove specific things in the area, you first need to put it in your inventory and/or your hotbar, right click it to edit what you want to remove and then start using that edited version (and when you are finished, free your hand like above).
With that method, it will stay in your inventory but you can always re-use it later as well (with the same setting or editing it first once more).

The only way to get more and more in your inventory would be if you are not using the key to free your hands but are putting it in your inventory instead, as far as I know at least.

[AlexMBrennan]

Holding shift and right clicking on it moves it to a trash slot but then robots take these garbage squares and use them to take up space in logistics chests.

Deconstruction planers work just like regular blueprints which means that you can delete them by clicking on the garbage can icon.

[Warlord]

That red square is the deconstruction planner. you must have put it onto a slot on your hotbar, and when you drop it from your hand it then has to go to inventory.

If you want to just use it and ditch it (I do all the time) then when you select the planner from the utility bar just press Q to drop it into oblivion.