To change the formatting of the shapes you can't select or on the locked layer, the only way is change the style of the shape in the Style in use box in Style pane.

1. Click Style tab at the bottom of the left docking pane to show the style pane, if the style pane has been opened.

   If not, on View menu, click Style Window, or click Style Window on standard toolbar to open the style pane.

2. Click Style tag on the style pane to switch to the Style table.

3. Click Show style and select Styles in use.

4. Select the styles applied to the shape you want to format.

5. Click the down arrow next the style bar, on the pop menu, click Edit the Style.

6. In the Formatting shapes window, select the options you want.

7. Click OK.

The most common example is the background of the page, you can select the background, but you can change the background style in Style pane.