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
void addActivationListener(ICellEditorActivationListener listener) {
        activationListeners.add(listener);
    }
    /**
     * Add columns to the tree and set up the layout manager accordingly.
     */
    private void addColumns() {
        
        TreeColumn[] columns = tree.getColumns();
        for (int i = 0; i < columnLabels.length; i++) {
            String string = columnLabels[i];
            if (string != null) {
                TreeColumn column;
                if (i < columns.length) {
					column = columns[i];
				} else {
					column = new TreeColumn(tree, 0);
				}
                column.setText(string);
            }
        }
        tree.addControlListener(new ControlAdapter() {
            public void controlResized(ControlEvent e) {
                Rectangle area = tree.getClientArea();
                TreeColumn[] columns = tree.getColumns();
                if (area.width > 0) {
                    columns[0].setWidth(area.width * 40 / 100);
                    columns[1].setWidth(area.width - columns[0].getWidth() - 4);
                    tree.removeControlListener(this);
                }