It's not possible to apply row width settings to the whole of the child Layout cell added to the parent Layout, instead within the child Layout (Template for Inlägg) you need to apply the desired width settings to the individual rows.
You can see in the screenshots where you can click to edit the row settings, which are currently set to only the container width.
OK i see, my problem was not about the columns width setting.
The problem seems to be the gallery not showing full width, when selecting first option.
When selecting other options the gallery seems to be narrow for some reason
Do not know if its a feature or a bug? Scroll down on page and see hidden link
The gallery picture sizes are fixed and as its not the desired way to display gallery in full size as there might be the chance that pictures displayed with gallery are blurred.
Maybe you can add the gallery to display in center or the row.
In addition to that just to let you know that Layouts plugin is added to maintanace mode so there will not be any further development or features added only the possible bug fixes will be entertained.
Thank you Nigel and Minesh for you answers.My issue is resolved (partly)now. Thank you!
Regarding image library, it seems like the size differs depending on how you want to display the pictures. So in my link i have 3 librarys but 2 of them differs in width depending setting.
Regarding removing layouts plugin, its sad because its a wonderful way of configure your page. Blocks are perhaps better from a programatically view, but as a designer its not top notch. More trial and error. not wysiwyg. But that is only my opinion.