Code completion/error markers broken when trying to use js_of_ocaml preprocessor

[endeavour]

I'm trying to use the OcaIde plugin for Eclipse with js_of_ocaml. Unfortunately the '##' syntax that js_of_ocaml uses for calling n-ary methods is upsetting the code completion.

I added the following comment to the top of the code to attempt to get OcaIde to run the preprocessor:
(* pp: -parser o -parser op -printer a -I /usr/lib/ocaml/js_of_ocaml/ pa_js.cmo *)

This seems to be doing something because I can see some rewritten variable names in the 'outline' view. Unfortunately it completely breaks the intellisense and I no longer get error markers (red squiggles) in the code.

The error logs fills up with the following error:

error creating error markers

org.eclipse.jface.text.BadLocationException
  at org.eclipse.jface.text.TreeLineTracker.fail(TreeLineTracker.java:1055)
  at org.eclipse.jface.text.TreeLineTracker.offsetByLine(TreeLineTracker.java:334)
  at org.eclipse.jface.text.TreeLineTracker.getLineOffset(TreeLineTracker.java:1122)
  at org.eclipse.jface.text.AbstractLineTracker.getLineOffset(AbstractLineTracker.java:169)
  at org.eclipse.jface.text.AbstractDocument.getLineOffset(AbstractDocument.java:922)
  at org.eclipse.core.internal.filebuffers.SynchronizableDocument.getLineOffset(SynchronizableDocument.java:382)
  at ocaml.views.outline.OutlineJob$1.run(OutlineJob.java:373)
  at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
  at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135)
  at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3563)
  at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3212)
  at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2701)
  at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2665)
  at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2499)
  at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:679)
  at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
  at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:668)
  at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
  at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:123)
  at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
  at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
  at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
  at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:344)
  at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  at java.lang.reflect.Method.invoke(Method.java:616)
  at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:622)
  at org.eclipse.equinox.launcher.Main.basicRun(Main.java:577)
  at org.eclipse.equinox.launcher.Main.run(Main.java:1410)
  at org.eclipse.equinox.launcher.Main.main(Main.java:1386)