The Width Selector panel flyout menu items are contextually sensitive and all items may not be available, depending on the current selection.
Width Selector Panel Flyout Menu
Inverts the current marker selection (selected width markers become unselected while unselected width markers become selected).
Selects all doubled width markers. Doubled width markers are defined as two consecutive width markers that are coincident (appear at exactly the same spot along the path); they can be used to create an abrupt change in stroke width along the path. The markers at point zero of a closed path are not considered doubled markers when using this menu item.
Changes each selected pair of doubled markers into a single marker, using the width of the trailing marker. The markers at point zero of a closed path are not considered doubled markers when using this menu item.
Width Selector Combine Selected Doubled Markers
To combine a pair of doubled width markers while using their average width, select only the doubled width markers, click the Average Widths button, and then use the menu item.
Changes all selected paths which are not already variable stroke width paths to variable width. This results in centered width markers at the start and end of the path with the path’s current width. This can be useful for applying the Vary Width Markers... menu item.
Changes the focal strokes on selected paths to uniform width (if they are not already). This removes all width markers; their width remains what was originally shown in the Control Bar or Stroke panel, which is equal to the maximum width among all the path’s width markers.
Width Selector Convert to Uniform Width
When marked with a check mark (the default), the panel shows controls which allow specifying the left and widths of each marker separately. Otherwise only the total width can be numerically specified. If you never use non-centered width markers, you may want to choose the menu item to uncheck it.
When marked with a check mark (the default), an informational line showing width marker counts, along with the Shift Selection Backward and Shift Selection Forward buttons, will be shown at the bottom of the panel.
Brings up the preference dialog (see Width Selector: Preferences).