First the tray icon. You can find these settings by right clicking the systray icon for DesktopX under Configure DesktopX. If you don't see the systray icon, you can get these settings by clicking on DesktopX in the start menu. If the systray icon isn't there, you can turn it on by unchecking the "No tray icon" in the DX settings/advanced tab. You can also unhide the icon by right clicking the start button and choose properties then taskbar and customize. Highlight your icon there and in the drop down choose how you want it to display that icon.
You can unhide the icons in the Configure DesktopX under the theme settings/desktop tab.(Note. Sometimes, if your icons are at the edge of the screen you can't see them, regardless of this setting. Unload DX move the icons away from the edge and reload it.)
If you don't save your settings for the theme(preferably as a new name), it will revert to the last saved theme after a computer restart. Right click the systray icon for DX and choose save theme before you exit windows.