Usually it happens when you draw the cell in LayoutXL, particularly when you insert pins.
Layer and purpose in these pins are selected separately for some reason, that is why it is easy to enter "impossible" combination.
Nothing happens, then you do it again and continue drawing. But there are several invisible squares that will continuously frustrate your inner perfectionist. You do the following:
Open this cell's layout, switch to Virtuoso window and enter:
lppList=list()
then:
foreach(shape hiGetCurrentWindow()~>cellView~>shapes if( (member(shape~>lpp lppList)==nil) then lppList=cons(shape~>lpp lppList)))
You have created the list with all layers in this layout, you can view it by entering:
lppList
You'll get something like this:
(("NW" "drawing")
("NP" "drawing")
("weird" "guy")
("M1" "pin")
("M3" "pin")
)
If you find a weird guy in this company, just enter the following command:
foreach(shape hiGetCurrentWindow()~>cellView~>shapes if((shape~>lpp == list("weird" "guy")) shape~>lpp = list("prBoundary" "drawing")))
If you see that some squares, labels (or whatever unseen before) appears as prBoundary, just delete it, save, and your layout will be small and shiny again.