To select a frame, click on it with the left mouse button.Double-clicking on a frame with the left mouse button selects the frame and automatically invokes the frame's properties dialog box.The currently selected frame is highlighted with a blue rectangular border.
  More than one frame can be selected at one time.To select more than one frames, start by selecting a single frame then use the standard Windows multiple-selection shortcuts of Ctrl+click and Shift+click to add to the selection. Ctrl+click on a frame adds that frame to the selected list (or removes it if the frame is previously selected) and Shift+click on a frame adds all of the frames between the last frame frame selected and the clicked one to the selected list.