@jonas3344 I’m not sure what kind of constraints you’re working with, so these options may not work for you, but usually if I expect someone to return to a grid, I either open the details in a new browser tab/window (using window.open()), or load the details in a dhx.Window, so that the grid is left untouched.
In one instance where I expected a user might open details for several rows, where I didn’t want them having to figure out which browser tab was which, I built a Tabbar with the grid in an uncloseable tab at index 0, then added a new closeable tab for each row they opened (or made active the relevant tab if one already existed for that row). That was in DHX5, so I can’t speak to how DHX6 might handle the grid headers now that the VDOM doesn’t keep the content of inactive tabs rendered, and would thus re-render the grid each time you switch back to the grid’s tab.
Maybe one of those solutions would work for you without having to fight the grid headers?