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
if (entry == rootEntry && isShowingCategories) {
            if (categories.length > 1
                    || (categories.length == 1 && !categories[0]
                            .getCategoryName().equals(
                                    MISCELLANEOUS_CATEGORY_NAME))) {
				return Arrays.asList(categories);
			}
        }
        
        return getSortedEntries(getFilteredEntries(entry.getChildEntries()));
    }
    /**
     * Returns the child entries of the given category
     * 
     * @param category The category to search
     * 
     * @return the children of the given category (element type
     *         <code>IPropertySheetEntry</code>)
     */
    private List getChildren(PropertySheetCategory category) {
        return getSortedEntries(getFilteredEntries(category.getChildEntries()));
    }
    /*
     * (non-Javadoc) Method declared on Viewer.
     */
    public Control getControl() {
        return tree;
    }