A bit of trouble with selection / descend

I've got a layout I'm messing with, and having a problem trying to edit-in-place (descend).

Problem is that the chip scribe and the chip core are in separate cells at the top level and seem to have identical extents. So I try and try to select the "core" but always get the "scribe". I've worked in other tools where if you have two selectable instances at a coordinate, click-select the one, if you click again the first will deselect and the second will select. This seems to not be the case here.

I would like to see whether there is a way to make the "selectable extent" of a cell, different than its data extents. If you have used Cadence you may know about the special behavior of the "instance" layer - in layout and symbol views, if there is an "instance" rectangle, this and only this becomes the selectable region. This is great for when you have (say) several large cells in a layout, which "step on each other" and underlie other "0 X" polygon and loose instances; odds are you'll select one of the big ones you didn't want, instead of the little one you did. I like to put cellname texts in the cell and then an instance rectangle around it - now there's just one "grab handle" right where you'd think to try, and elsewhere the cell is "inert".

Maybe the hierarchy browser is the only way to deal, presently, but thought I'd suggest this feature and inquire whether it might exist (or, whether a similarly-behaving alternative comes to mind). And ask for suggestions about how to make selection choose between coincident objects so I get the one I wanted.


  • I'm also seeing what I think is improper "selection scope" in release 25.8.

    When I display full hierarchy, I find that every polygon, all the way down, seems to be selectable. I believe this is not right; objects contained in lower level cells ought to not be selectable by click, only objects within the cell-level context.

    Is this meant to be like it is? Or is there a setting similar to display hierarchy, that controls "select hierarchy" behavior?

  • Hi Jim,

    You can turn off "select inside hierarchy" by enabling "View/Select Top Level Objects". After this you can only select objects on top level.

    And KLayout does cycle through the selection if there are many selectable objects in the scope. Just keep clicking. I'm not 100% sure that this works with all hierarchical configurations, but it should on top level.


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