Bug 258016 [PropertiesView] NPE in org.eclipse.ui.views.properties.PropertySheetViewer
At line 720. If the selection is null this will result in an NPE. Here is the offending code snippet: 714: // get the new selection 715: TreeItem[] sel = new TreeItem[] { selection }; 716: if (sel.length == 0) { 717: setMessage(null); 718: setErrorMessage(null); 719: } else { 720: Object object = sel[0].getData(); // assume single selection It would be better replaced with the following (sorry, no patch, I'm not set up for editing the platform!): // get the new selection TreeItem sel = new TreeItem[] { selection; if (selection == null) { setMessage(null); setErrorMessage(null); } else { Object object = selection.getData(); // assume single selection if (object instanceof IPropertySheetEntry) { // get the entry for this item IPropertySheetEntry activeEntry = (IPropertySheetEntry) object; // display the description for the item setMessage(activeEntry.getDescription()); // activate a cell editor on the selection activateCellEditor(selection); } } In fact, I'm not at all sure why the selection was being wrapped in a single element array at all, I'm guessing a holdover from old code?
bundles/org.eclipse.ui.views/src/org/eclipse/ui/views/properties/PropertySheetViewer.java
* 
     * @param listener
     *            a cell editor activation listener
     */
    
    void removeActivationListener(ICellEditorActivationListener listener) {
        activationListeners.remove(listener);
    }
    /**
     * Remove the given item from the tree. Remove our listener if the
     * item's user data is a an entry then set the user data to null
     * 
     * @param item
     *            the item to remove
     */
    private void removeItem(TreeItem item) {
        Object data = item.getData();
        if (data instanceof IPropertySheetEntry) {
			((IPropertySheetEntry) data)
                    .removePropertySheetEntryListener(entryListener);
		}
        item.setData(null);
        
        
        entryToItemMap.remove(data);
        item.dispose();
    }
    /**
     * Reset the selected properties to their default values.
     */