All desks with desk numbers between first desk and last desk are displayed. If last desk is omitted only the first desk is shown. If both desk numbers are omitted, the current desk is used instead. If you use an asterisk '*' in place of first desk the pager will always show the current desktop, even when you switch desks.
Example lines to put in your .fvwm2rc:
Module FvwmPager 0 3or
Module FvwmPager *or from within an fvwm pop-up menu:
AddToMenu Module-Popup Modules Title + Audio Module FvwmAudio + Auto Module FvwmAuto 200 + Buttons Module FvwmButtons + Console Module FvwmConsole + Ident Module FvwmIdent + Banner Module FvwmBanner + Pager Module FvwmPager 0 3or
+ Pager Module FvwmPager *
If the pager is started with the -transient option, the next time a button is released the pager is closed. Note that this option does only work if the window style of the pager window is 'sticky' (see fvwm2 man page). You should use the 'StaysOnTop' style too.
Example:
Style FvwmPager Sticky, StaysOnTop *FvwmPager: Rows 1 *FvwmPager: Columns 1 Mouse 3 R C Module FvwmPager -transient
With this in your .fvwm2rc, if you press control and button 3 in the root window the pager pops up under the mouse and while the viewport moves with the mouse.