Exception when using UIMA's Annotation Browser View - eclipse

Question

When using the UIMA workbench in eclipse, I occasionally run into a NullPointerException when trying to open the Annotation Browser View.
This doesn't occur every time. This is only happening when I run a pipeline which overwrites an existing (potentially opened xmi file).
I have no idea how to fix that and haven't found anything online.
Any suggestions what I could do?
Thanks!
I get the following message (mulitple times) in my errorLog.
Problems occurred when invoking code from plug-in: "org.apache.uima.caseditor".
java.lang.NullPointerException
at org.apache.uima.ruta.caseditor.view.tree.AnnotationTreeViewPage.dispose(AnnotationTreeViewPage.java:384)
at org.apache.uima.caseditor.editor.CasEditorViewPage.setCASViewPage(CasEditorViewPage.java:202)
at org.apache.uima.caseditor.editor.CasEditorView.createViewPage(CasEditorView.java:123)
at org.apache.uima.caseditor.editor.CasEditorView.access$000(CasEditorView.java:49)
at org.apache.uima.caseditor.editor.CasEditorView$2.casDocumentChanged(CasEditorView.java:162)
at org.apache.uima.caseditor.editor.AnnotationEditor$6.run(AnnotationEditor.java:1012)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
at org.apache.uima.caseditor.editor.AnnotationEditor.doSetInput(AnnotationEditor.java:1009)
at org.eclipse.ui.texteditor.AbstractTextEditor.setInputWithNotify(AbstractTextEditor.java:4248)
at org.eclipse.ui.texteditor.AbstractTextEditor.setInput(AbstractTextEditor.java:4268)
at org.apache.uima.caseditor.editor.AnnotationEditor.handleElementContentReplaced(AnnotationEditor.java:905)
at org.eclipse.ui.texteditor.AbstractTextEditor$ElementStateListener.lambda$3(AbstractTextEditor.java:466)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:40)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:185)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3919)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3550)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1173)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1062)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:155)
at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:635)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:559)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:150)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:155)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:203)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:137)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:107)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:400)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:255)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:660)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:597)
at org.eclipse.equinox.launcher.Main.run(Main.java:1468)