I am using gentoo, current kernel gentoo-sources-4.1.12 ; issue occurs on different kernel versions. After booting system and starting X- server (or reaktivating laptop from sleep) the desktop is flooted by xfce4-dislpay-settings dialogs. It stops after 2 or 3 minutes when (i think) it hits the maximum window limit (must be around 205 I guess). It might be in correlation with ACPI problems. At the same time I receive following messages: "ACPI event unhandled: video/switchmode VMOD 00000080 00000000" respectively after changing ACPI default.sh I get something like "^@" Please, I need help. It is neary impossible to use the system in the first 5 minutes. Tested on different xfce4-settings versions!
Delete the XF86Display shortcut from Settings Manager > Keyboard > Application Shortcuts to stop the dialogs, then look at resolving your ACPI issue.
This issue should be resolved with this commit. https://git.xfce.org/xfce/xfce4-settings/commit/?id=786c0dc49dd10b092d1bf6d91223d8e148800146 With this, the minimal dialog becomes a single instance application, so the number of displayed windows will be reduced to 1.