so my future workaround will be, if I want to use the grid properly, i have to set up the first wall directly to 0/0 on the grid. so the first room can be attached to 0/0. like this:
https://bilderupload.org/image/eaae87200-screenshot-2022-11-11-181.jpg
from now on, every wall will be easier to ...

or is that a bug, that walls don´t snap to the grid?

yes, I use your suggestion as a workaround. There is potential to make that more comfortable without to have to do that.
Maybe you might be able to add an option "use 0/1/2 decimal". With that option I would not have to edit with enter.

https://bilderupload.org/bild/24f081752-screenshot-2022-11 ...

hi, I tried to construct 2 walls with diffrent zoom (about zoomfactor 2) and the walls have exacly the same weird ",1 cm" measurements. I think the magnetism could be better if it would snap to a 1cm grid. - at least for me.

I try to upload screenshots. the two walls are build by mouse and are ...

hi,
not quite. in other words: I would like to edit walls in cm steps with the mouse. in version 7.0 my mouse movement produces mm steps on x and y axis. 1cm steps would be much easier to handle. (or 0,5cm)

Is there a way to set the x-y Grid to cm steps?

it is really hard to move objects and build walls in mm steps. I would like to use cm steps. That would be accurate enough and would be much easier to handle.
is there a way to set up that configuration?