How to show undo and redo actions in toolbar in rcp application

I am working on an rcp application with a toolbar for quick access to certain actions, including undo and redo. My problem is that these two specific actions don't show up in the toolbar. I have located the cause to the workbench.xmi file that is generated when the application launches. A tag persistedState with an attribute key="persp.hiddenItems" contains persp.hideToolbarSC:org.eclipse.ui.edit.undo,persp.hideToolbarSC:org.eclipse.ui.edit.redo in the value="..." attribute. If I delete these entries from workbench.xmi, the undo and redo actions show up in the toolbar as they should.

My question is: What can I do so that org.eclipse.ui.edit.undo and org.eclipse.ui.edit.redo don't end up in this attribute to begin with?

I originally used eclipse neon without this problem, but when updating to eclipse 2018-12 this started happening.

Edit:

I finally got it to work by changing the IDs of my undo and redo actions to something else. I had to set the ID with setId(...) and setActionDefinedId(...) in the actions' constructors, and then the commands had to be defined in plugin.xml under <extension point="org.eclipse.ui.commands"> in a <command id="..." name="Undo"></command> tag.

This solutions feels more like a workaround than an actual solution, but it works for me.

Solution

This is set by the hiddenToolBarItem element of the org.eclipse.ui.perspectiveExtensions extension point.

The org.eclipse.ui.ide plug-in uses this to disable these tool-bar items:

  <extension
         point="org.eclipse.ui.perspectiveExtensions">
      <perspectiveExtension targetID="*">
         <!--
              disable "print" button which is defined by org.eclipse.ui.actions.ActionFactory.PRINT
              and contributed by org.eclipse.ui.internal.ide.WorkbenchActionBuilder
         -->
         <hiddenToolBarItem id="print" />
         <!--
              disable "undo" button which is defined by org.eclipse.ui.actions.ActionFactory.UNDO
              and contributed by org.eclipse.ui.internal.ide.WorkbenchActionBuilder
         -->
         <hiddenToolBarItem id="org.eclipse.ui.edit.undo" />
         <!--
              disable "redo" button which is defined by org.eclipse.ui.actions.ActionFactory.REDO
              and contributed by org.eclipse.ui.internal.ide.WorkbenchActionBuilder
         -->
         <hiddenToolBarItem id="org.eclipse.ui.edit.redo" />
      </perspectiveExtension>
   </extension>

I don't see a way to clear this other than leaving out the plug-in.