Cant mirror desktop between laptop and projector

[starworks]

When I connect my laptop to a projector, the projector becomes my primary
monitor and my laptop screen goes black. The function key combo won't work to
switch displays. I can't switch the displays in the change display panel
(i.e. set up my laptop as the primary monitor - the option is greyed out).
When I turn the presentation feature on in the control panel it doesn't
detect another monitor that I can switch the settings for. I need to do my
presentations with my desktop on both my laptop and the projector. Does
anyone know a work around? Thanks

 

[Curious]

Contact your laptop vendor.
On any laptop I have ever used the Fn function key option has always
permitted Laptop only, Other display only, or both.

 

[Guest]

When I connect my laptop to a projector, the projector becomes my primary
monitor and my laptop screen goes black. The function key combo won't work to
switch displays. I can't switch the displays in the change display panel
(i.e. set up my laptop as the primary monitor - the option is greyed out).
When I turn the presentation feature on in the control panel it doesn't
detect another monitor that I can switch the settings for. I need to do my
presentations with my desktop on both my laptop and the projector. Does
anyone know a work around? Thanks

set the laptop screen and the external screen resolutions to the same
value and see
if that makes any difference.