Problems with object snapping

Hello Rhino experts!

I have Rhino 8 and am an enthusiastic beginner. I need your help please. I have inserted objects as DWG and want to model the furniture with Rhino. There are problems with extrusion. I can’t adjust the gray element to the green height directly. Rhino doesn’t catch the point. It works with new elements. But not here. What am I doing wrong? Please help me. Thank you and kind regards from Austria Ben

it could be that the dimensions of the geometry are way too small, or the origin is way off. can you share that file?

hi @Benjamin_Treml see also this info for more efficient support