question about ()

hi ..

i am here as a quest. and is here because my gf have wondered about a question related to her education in " building engineer ".

so to surprise her and give her a little info. i have this little question.

when she run solidworks. there are some names on the left panel. containing the different objects. and so on.

but on some of the name. it have this text/symbol.

( - )

can anyone please explain to me what that mean ??

and if its nessary or something she could have done by mistake.

she always wonders what that text/symbol means.

thz//hugblue.

SolidworksDrawings And Detailing