In order to enable this feature, open the Settings notebook for the folder for which you wish to enable this feature. On the "XFolder" page therein, check the "QuickOpen" flag.
After the next WPS startup, XFolder will then read in the contents of that folder and load all the icons. Note that XFolder only does this right after the WPS has booted, so changing the "QuickOpen" flag of a folder has no immediate effect.
Depending on how many folders have the "QuickOpen" flag set, WPS bootup might
take quite a while. Reading all the icons does not become faster by using this
feature. The only difference is that the icons are read earlier.