Hallo Matthias,
ich bekomme den Fehler nicht. Kannst Du bitte nochmal im Logfile nachsehen, was da steht? Da müßte die NullPointerException auch nochmal auftauchen.

Hallo Ralf,

ich bekomme den Fehler auch unter Linux.
eclipse.buildId=2.0.2.
java.version=1.8.0_181
java.vendor=Oracle Corporation
BootLoader constants: OS=linux, ARCH=x86_64, WS=gtk, NL=de_DE
Command-line arguments: -os linux -ws gtk -arch x86_64

!MESSAGE Internal Error
!STACK 0
org.eclipse.e4.core.di.InjectionException: java.lang.NullPointerException
	at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:65)
	at org.eclipse.e4.core.internal.di.InjectorImpl.invokeUsingClass(InjectorImpl.java:305)
	at org.eclipse.e4.core.internal.di.InjectorImpl.invoke(InjectorImpl.java:239)
	at org.eclipse.e4.core.contexts.ContextInjectionFactory.invoke(ContextInjectionFactory.java:132)
	at org.eclipse.e4.core.commands.internal.HandlerServiceHandler.execute(HandlerServiceHandler.java:152)
	at org.eclipse.core.commands.Command.executeWithChecks(Command.java:494)
	at org.eclipse.core.commands.ParameterizedCommand.executeWithChecks(ParameterizedCommand.java:487)
	at org.eclipse.e4.core.commands.internal.HandlerServiceImpl.executeHandler(HandlerServiceImpl.java:210)
	at org.eclipse.e4.ui.workbench.renderers.swt.HandledContributionItem.executeItem(HandledContributionItem.java:431)
	at org.eclipse.e4.ui.workbench.renderers.swt.AbstractContributionItem.handleWidgetSelection(AbstractContributionItem.java:446)
	at org.eclipse.e4.ui.workbench.renderers.swt.AbstractContributionItem.lambda$2(AbstractContributionItem.java:472)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:86)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:5348)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1348)
	at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4602)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:4183)
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1150)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:336)
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1039)
	at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:153)
	at org.eclipse.e4.ui.internal.workbench.swt.E4Application.start(E4Application.java:162)
	at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:134)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:388)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:243)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:653)
	at org.eclipse.equinox.launcher.Main.basicRun(Main.java:590)
	at org.eclipse.equinox.launcher.Main.run(Main.java:1499)
	at org.eclipse.equinox.launcher.Main.main(Main.java:1472)
Caused by: java.lang.NullPointerException
	at com.sebulli.fakturama.handlers.MarkOrderAsActionHandler.markOrderAs(MarkOrderAsActionHandler.java:199)
	at com.sebulli.fakturama.handlers.MarkOrderAsActionHandler.run(MarkOrderAsActionHandler.java:315)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:55)
	... 33 more

Gruß
moped

Hallo zusammen,
ich glaube, das liegt an der in den Produkten hinterlegten Menge. Da hatte ich nicht bedacht, daß da ggf. gar nichts drinstehen kann. Wenn ihr bei "Menge" eine 1 oder irgendwas in der Art eintragt sollte es klappen.
In der aktuellen Beta-Version habe ich das bereits korrigiert.