OS: Ubuntu 20.04 (Xubuntu) beta
DE: Xfce 4.14
Power Manager version: 1.6.6-1
Device: Notebook (Toshiba Sattelite Pro B-40 A)
GPU: Intel HD 4000 (integrated)

Hi, thank you for the Xfce. I'm using Xubuntu 20.04 (Xfce 4.14) beta. The OS came with screensaver (xfce4-screensaver) on by default though today all the monitors are LCD and most of the users don't use screensaver. It's also a battery unfriendly default. The screensaver by default is a empty black screen (!) and it was causing problem with display turning off. So I've turned the screensaver off to see if xfce4-power-manager can do it's work normally. I think I've found 1/2 bugs with the xfce4-power-manager's function-

Unexpected behaviour #1: When the option "Display Power Manager" is on, screen goes blank after 5 minutes though "Blank after" timeout is set to "never".

Unexpected behaviour #2: When the option Display Power Manager is off, xfce4-power-manager ignores the "Blank after" timeout and always blank the screen at 5 minutes. 
Though the "sleep after" and "switch off after" option is grayed out when DPM is off, the "Blank after" timeout remains configurable.



My suggestion:-
3 separate similar setting in the Display tab of xfce4-poer-manager maybe confusing for laptop users.Regarding the "Blank screen" option, I've never saw anyone who set their display to go show a black screen with full backlight on (so not saving any power either). If there is some use case (maybe for OLED screens which are still rare) please consider putting this function in any advanced section, disabled by default so normal laptop users don't think there's a bug when their display shows a black screen while remaining on. 
Considering the other 2 options ("sleep after" and "switch off after"), power manager should show a short info (when one hovers their mouse over the settings) about what the "switch off" function is so not to confuse users who always use laptops (as this settings is foreign to them and there's no seemingly difference between sleep and switch off function to general laptop users).
Or, consider making those two settings as one option for laptop users like other OSes (unless the "switch off" has power advantage over "sleep" option on laptops).
I'm not a programmer (or anything related) so I apologize if I'm not technically right about something.