Component area becomes fluid after adding module to sidebar

I found out that if you add the class "container" to the Helix Ultimate template at [Layout] > "Main Body" > [Row Options] > "Custom CSS Class" that it works almost perfect.
In that same screen you see "Fluid Width". You expect that setting this to disabled that the content area won't be full width but it is necessary to add the class "container" to prevent full width.

This looks like a bug!

Hi Mehtaz,

The site is in development and needs een login to visit.
I'v added visitor frontend login in de hidden content field of this forum post.
The site is now on Joomla 4.1.4.

At the moment the class "container" is added to the section "sp-main-body". So this makes it almost perfect. There is only some padding or margin on the right which is not quite right at the moment.
If you change <section id="sp-main-body" class="container"> with your dev tools from your browser to <section id="sp-main-body"> you see what happens.
You do need a large desktop screen to see the problem.
See image from my previous post.
There is also a "Test" page in the menu. This page is an original Joomla article page (not a SP Page builder page).
On this page the class "container" isn't necessary.

Hope to hear from you soon.

Jeroen

No, it is not solved!
I just used a workaround to let it look ok.
I think it is a bug. Just read this whole thread.
In short. If in helix ultimate "Main Body" "Fluid Width" is off and you make a page with SP Page Builder and add a custom module in the left or right position next to the component area the page becomes fluid despite "Fluid Width" in Helix ultimate is set to off.

This looks very like a bug.
I would like a developer looks at this problem.