Bug 298835 Merge e4 Project Path Variable back into the 3.6 stream
The virtual folder and filters changes are already in 3.6, the project path variable changes in e4 still remains to be merged.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/dialogs/PathVariablesGroup.java
initTemporaryState();
            
            return true;
        } catch (CoreException ce) {
            ErrorDialog.openError(shell, null, null, ce.getStatus());
        }
        return false;
    }
    /**
     * Removes the currently selected variables.
     */
    private void removeSelectedVariables() {
        
        int[] selectedIndices = variableTable.getSelectionIndices();
        for (int i = 0; i < selectedIndices.length; i++) {
            TableItem selectedItem = variableTable.getItem(selectedIndices[i]);
            String varName = (String) selectedItem.getData();
            removedVariableNames.add(varName);
            tempPathVariables.remove(varName);
        }
        updateWidgetState(null);
    }
    private boolean canChangeSelection() {
        int[] selectedIndices = variableTable.getSelectionIndices();
        for (int i = 0; i < selectedIndices.length; i++) {
            TableItem selectedItem = variableTable.getItem(selectedIndices[i]);
            String varName = (String) selectedItem.getData();
            if (isBuiltInVariable(varName))
                return false;