This Bugzilla instance is a read-only archive of historic NetBeans bug reports. To report a bug in NetBeans please follow the project's instructions for reporting issues.
Originally spotted in apisupport project, same thing happens in j2se project (when removing jar from Test Libraries): When removing unit test library, with class referenced from test, error badge shows up neither in editor nor on file node in project window. After clicking into editor, badge shows up on affected line, but you have to actually change something and save the file to update editor tab and file node.
Seems to be fixed in the current dev build.