Within the “Slide Show - Slide Show Settings” Do you have the “Multiple Displays” setup correctly?
<Slide Show Settings;
Multiple Displays
By default the primary display is used for slide show mode. If the current desktop is displayed on more than one display, you can select which display to use for full screen slide show mode. If the current desktop spans only one display, or if the multi display feature is not supported on the current system, you cannot select another display.
Presentation display
Select a display to use for full screen slide show mode.
If the system allows the user to span a window over all available displays, you can also select “All displays”. In this case the presentation is spanned over all available displays.
Maybe I want too much! I want the presentation console to be windowed, but the presentation display to be full screen. That is, I want my laptop to have a windowed presentation console so that I can do other things at the same time, but I want the external monitor to be full screen without the menu.
What I really ultimately want is some sort of setup where I have multiple windows on my laptop, and I choose which one is displayed on the external screen. That way, during the presentation, I can pull up an Internet browser window, display that in between slides if I should so want, and maybe pull up e-mail and show that full screen or maybe just read my e-mail while doing the presentation. Looks like others would have that desire too. I have seen some places where they have edited the next slide while at the same time showing the previous slide. That’s what I had hoped “windowed” would do, but that obviously isn’t possible with Impress. Next best would be able to do other things while the external monitor is full screen without a menu.
Note that with Gnome you still have other workspaces to use other applications while the presentation is running, try “CTRL”+“ALT”+“Down arrow”.
OK, you can do that, to an extent. As usual there are 101 ways to do the same thing in Linux, so here is my take.
Assumptions:
Gnome default setup (no mods to KBD shortcuts), “Join display” and “Workspaces only span primary display” (i.e. the laptop LCD).
“Presenter console” disabled in Impress (Tools > Options > Impress > General > untick “Enable Presenter Console”)
“Slide Show” > “Slde Show Settings” > “Full Screen”
Open a presentation, go to the slide you want to display, edit as desired, then click SHIFT+F5 (current slide goes full screen on the external display).
Meanwhile, on the laptop LCD you can still view other slides in the “Windowed” Impress and edit graphics objects; you cannot edit text since the keyboard is “captured” waiting for presentation shortcut commands (try “N” and “P” for instance).
Any time you can hit “ESC”, edit a slide in the LCD, then “SHIFT+F5” shows it full screen on the external monitor.
While the presentation is running, let’s go to another workspace and open another app (say, Firefox).
“CTRL+ALT+down arrow” enters the next workspace (on the LCD, the full screen slide should remain on the external monitor) and open Firefox (“SUPER AKA WinKey+ type ‘firefox’ +ENTER” does it in standard Gnome).
As long as the Firefox window remains into active focus you can do whatever you want with it.
Want to show it on the external monitor? You have to drag it to the right so that most of the window shows on the external monitor, then “SUPER AKA WinKey+up arrow” sends it full-screen (F11 also works for Firefox, but that depends on the specific application).
“SUPER AKA WinKey+down arrow” returns Firefox to normal size, so that you can drag it out of the way when finished.
Now enter the third workspace with “CTRL+ALT+down arrow” and open a third app, say Calc.
To show it in the external monitor drag to the right; when most of the window is shown on the external monitor “SUPER AKA WinKey+up arrow” sends it full-screen (“CTRL+SHIFT+J” would send it full screen on the laptop LCD but that is specific to Calc).
“SUPER AKA WinKey+down arrow” returns Calc to normal size.
To navigate through workspaces and the respective applications showing there try “CTRL+ALT+up arrow” and “CTRL+ALT+down arrow”.
While Impress has a shortcut to go full-screen on the external monitor (F5 or SHIFT+F5), in general other apps need to be dragged beyond the right hand side of the LCD “primary display” (unless a given app has dedicated provisions to do that).
For those of us used to Gnome it is easier done than written, but I understand that it might take a bit of training for users coming from other DEs.
Weird! Maybe you have Gnome as an additional DE and the display manager is still SDDM (from Plasma) and so you see the same settings as with KDE?
Here (on a laptop) I can even hit Fn+F8 (might be different on other keyboards) to cycle through “Mirror”, “Join Displays”, “External Only” and “Built-in Only”…
When I go into the presentation, SHIFT+F5 seems to do nothing different than F5.
That is normal if Impress is focused on the first slide: F5=start from first slide, SHIFT+F5=start from current slide.
When I press “CTRL+ALT+down arrow”, it doesn’t switch workspace.
I checked with Gnome, Gnome Classic, Gnome on X11 and all switch workspace that way. Only difference, Gnome Classic has 4 (fixed) workspaces, the others dynamically adjust on demand (unless you tweak default preferences).