Why can not DELETE this sketch

[ehgml50]

I just drawing Arc in 'Sketch41'

But 'Sketch41' can't delete

Also When I right-click, there is no DELETE Button

So I want to know why can't delete this sketch

[SharkDesign · Accepted solution]

That sketch is shared, so it is being used by something else. 

You need to delete the other item using this sketch too. 

[johnsonshiue]

Hi! Please feel free to share the file here. Forum experts can help take a further look.

Many thanks!