In a substance’s limit-value list, the Show all OELVs toggle reveals the full set of exposure limit values, including the entries that are hidden by default.
That toggle now stays on for the current session only by default. If you flip it once to take a look, your next visit starts in the default view again, so you are never unknowingly stuck in the expanded view.
Prefer to always work with every limit value in view? Tick the new Remember checkbox next to the toggle. The preference is then stored on that device and applies on your next visit too. Turning the toggle back off clears the stored preference automatically.