Selecting Elements in Objects and Timeline
Now that you’ve created a couple of elements, you’ll want to know how to select and modify them. Let’s start with some basic rules for selecting.
Using the Selection tool, click the white background in the design view. This is also the LayoutRoot element.
Hover over the gray canvas element and the rectangle that you added at the end of the last section. Notice the blue bounding box that appears when you hover above each element.
Click and drag the gray canvas. The canvas and the box inside move together.
Now, choose Edit > Select None, or press Ctrl+Shift+A. Then click and drag the white square. It moves independent of the gray canvas.
Since elements are nested one inside the other in the Expression Blend layout model, selection is a bit more sophisticated than you may be used to and it can get confusing if you don’t observe the rules of the road.
If there are no elements selected, any element, regardless of its nested position in the object tree, can be selected with the Selection tool. Once an object is selected Expression Blend prevents you from selecting children of the element to prevent unwanted or unexpected dragging of child elements. It takes a bit of getting used to, but it’s fairly intuitive once you get the hang of it. To avoid this, you can click the LayoutRoot to deselect an element, or choose Edit > Select None.
The easiest way to get used to this is a little practice. Using the Selection tool, click LayoutRoot, then click on the ChildCanvas control in the Objects and Timeline panel. Then drag the ChildCanvas.
Now release the selection of the ChildCanvas by clicking on LayoutRoot in the Objects and Timeline panel. Now click and drag the white square. Each time you select LayoutRoot it clears the current selection and allows you to select any element in the tree. Repeat this process a few times to get the feel for it.
You are done with this file, you can choose File > Close All Documents. When the Expression Blend dialog box appears, press Don’t Save.