When experiencing bugs with the xfce4-power-manager component, your way of helping things getting fixed is to report a bug about it in bugzilla.
Note: For this you will need to have/create an account.

• [Bug 15470] xfce4-power-manager - notifications timeout is hardcoded / not managed by xfce4-notifyd (2019/05/25 23:48)
• [Bug 15444] Change systray/system tray to notification area (2019/05/22 00:07)
• [Bug 15387] xfce4-power-manager-settings segfaults in g_type_check_instance due to upower's untimely auto removing USB UPS (maybe) (2019/05/11 21:10)
• [Bug 14716] Power manager is not blank screen (2019/05/11 12:20)
• [Bug 14864] my laptop never powers off (2019/05/11 12:18)
• [Bug 15111] xfce4-power-manager blocks screensaver (2019/05/11 12:18)
• [Bug 15300] Laptop lid action not respected (2019/05/08 00:35)
• [Bug 15363] Low power pop-ups do not disappear after plugging in (2019/05/05 11:23)
• [Bug 15158] Logout window focusses "Cancel" by default AND/OR add reaction time delay for usage (2019/05/01 22:43)
• [Bug 15331] Use systemd-logind methods instead of polkit permissions (2019/04/27 12:55)
• [Bug 15231] Power Manager Plugin tray icon size (2019/04/26 22:39)
• [Bug 15330] Power Manager does not sleep monitor when enabled, monitor never sleeps (amdgpu,freesync) (2019/04/26 21:05)
• [Bug 11339] Add support for logind hybrid sleep when closing lid (2019/04/26 00:19)
• [Bug 15310] Incorrect use of org.*.ScreenSaver DBUS services (2019/04/20 20:43)
• [Bug 14845] Google Chrome inhibiting power management appearing twice (2019/04/01 17:46)
• [Bug 15180] screen remains blank on any activity (2019/03/08 17:13)
• [Bug 15162] Presentation Mode to inhibit suspend on lid close? (2019/03/01 12:30)
• [Bug 15151] Unable to override logind lid open/close handlers (2019/02/20 19:06)
• [Bug 15134] laptop backlight adjustment mismatch (2019/02/11 18:12)
• [Bug 15129] Display power management sliders should not require 1 minute separation between blank/put to sleep/switch off (2019/02/08 10:35)

If your bug/problem has not been reported before, report a new bug. Please ensure that you disclose any information that might be relevant for developers reading the bugreport, e.g. what distribution you're using, what package-version of xfce4-power-manager or related Xfce libraries etc. To report a new bug, go here.