The vertical cursors in the LWA products are very powerful measurement tools, especially their ability to "snap" to the brightest peak within the highlighted region. You may assume that clicking anywhere in the shaded region would trigger a peak find within that region; however, that isn't the intended behavior. While the cursors seem fairly intuitive to use, here are some tips and tricks to help you better understand some of the nuanced behavior of these cursors.
Clicking within the shaded area selects the cursor and moves it to the mouse location. This makes it easier (particularly on a touch screen) to select and move the cursor. Otherwise it can be difficult to click precisely on the cursor to select it.
When the user selects the cursor and moves it at least 2 pixels, the cursor simply moves to the new location. It does not snap to a peak.
Clicking directly on (or very close to) the cursor will make the cursor search for the highest peak in the currently highlighted area. Double-clicking the cursor has the same effect, but the cursor is thin enough that it's actually difficult to double-click the cursor itself instead of the area around it. When the user selects the cursor, holds the button down, and releases without moving it, the cursor snaps to the peak.
The combination of these gestures makes it easy to freely move a cursor and then touch it again if the user did want the cursor snapped to the peak.