This is where Google takes you if you’re searching “unreal how to prevent selecting the floor” and I’m also looking at my desktop clock, 2024, and the only solution I’ve actually found is something I don’t fully understand, but you experienced people do. Credit goes to Dragonsleeve on reddit:
What I did was put the actor in a sublevel, then lock the entire sublevel.
To first create the level
- Windows tab at top of editor, select Levels in dropdown
- Menu pops up, under Levels tab select “Create New”
- Choose “Empty Level”
- Name the level whatever you want
It should show up as a sublevel beneath Persistent Level. To move actors, in the same window right click the level and select “Move Selected Actors to Level”.
Once you have all the actors you want moved, save the level and click the lock symbol (all within the same Levels browser). If done right, the actors should turn grey in World Outliner.