Hello we have problems

Hello, we installed your plugin, everything works fine, but we encountered some problem.
When loading the theme preloader, your flexible menu is hidden, we want the menu not to be hidden under any circumstances
We have assigned z -index – 99999 !important to all classes, which you specified in the instructions, as well as site -header , but the menu is still hidden while the page is loading.
But with the bottom menu (another bottom menu plugin), everything is ok