Markers can be resized in one of the following ways:

 

Click anywhere on the marker to select it. When the marker is selected, three points will appear:  a resizing handle at the left- and right-boundaries, and a point in the center for moving the marker. Position the mouse cursor over one of the resizing handles so it turns into a two-headed arrow.  While holding the mouse button down, move that marker boundary to a new position. Release the mouse when the marker is the desired size.

 

With the plot containing the marker you want to delete in selected or edit mode, use the Format1D OptionsMarkers command. This brings up a Formatting Markers dialog. In the Marker list box, highlight the marker you want to resize. The low and high parameters represent the channel numbers of the left and right marker boundaries, respectively. Change the low and high parameters by either typing in new numbers or using the arrow buttons to incrementally change the numbers, decimal values may also be used. Click OK.

 

Right-click on the plot containing the marker and select Format from the pop-up menu. Choose the Markers category in the formatting dialog. Highlight the marker you want to resize in the list box. The low and high parameters represent the channel numbers of the left and right marker boundaries, respectively. Change the low and high parameters by either typing in new numbers or using the arrow buttons to incrementally change the numbers. Click OK.