Thanks Its Work Again!
I have Also That problem. If i open perl document i became this error: Problems occurred when invoking code from plug-in: "org.eclipse.jface". Exception Stack Trace java.lang.NullPointerException at org.eclipse.e4.ui.internal.workbench.PartServiceImpl.internalFixContext(PartServiceImpl.java:449) at org.eclipse.e4.ui.internal.workbench.PartServiceImpl.bringToTop(PartServiceImpl.java:410) at org.eclipse.e4.ui.internal.workbench.PartServiceImpl.showPart(PartServiceImpl.java:1187) at org.eclipse.ui.internal.WorkbenchPage.busyOpenEditor(WorkbenchPage.java:3261)...