What are the rules with Floating Groups

I am using a sliding menu which uses a floating group. I have a second menu that acts like a visible extension to the sliding menu and it slides by virtue of being pushed in and out by the sliding menu. I also have a page header that is also pushed in and out by the sliding menu.
You can see below how this operates. You can see the red sliding menu, the thin extension menu with the hamburger icon, and the header with the top image but at the end you can see that scrolling causes the header and menu extension to scroll off the page:

The beginning of the GIF is how I want this to work and to look. The trouble is that the header and the menu extension should be floating groups so that they don’t scroll up and off the page, which is what happens when they are regular groups. When these are floating groups, they don’t slide up and off the page but then they do cover the sliding menu as seen here:

Is there any way these three floating groups to coincide with each other and act appropriately?

You wouldn’t get the floating header to slide…what you could do is add a border on the left that is the same width as the side menu for when the side menu is visible and that should move the elements in the floating header over to the right by that amount of space.

The side menu should be set to float above elements, which it looks like it is…you may want to right click and select ‘bring to front’ to try and get it to be on top of the floating header when it is visible.

Another option would be to use some CSS to set the Z-index so it will be above the floating header for sure.

What I was trying to do with the header is not cover it, but to slide it to the right. I found out that the sliding menu plugin allows for a header which solves the problem that allows the header to shift properly when the sliding menu is made visible but I’m stuck with the skinny menu not moving. It moves when it’s a group, but not when it’s a floating group, hence the purpose of the floating group, but I may need to address it with the CSS as suggested if that’s possible.