There are two "constraints" settings on the view menu: "Show constraints" and "Show ligand constraints".
The setting for "Show ligand constraints" is saved in options.txt under "view_options/show_catalytics_csts".
The setting for "Show constraints" is not saved to options.txt, and so the checkbox always reverts back to being checked when the client is restarted.
There is a previous "Show Constraints" feedback which states that "Show ligand constraints" was originally called just "Show constraints".
If this is true, perhaps the "Show constraints" option no longer has any purpose and could be removed.
If "Show constraints" still has a function, its setting should be preserved in options.txt.
If both "constraints" options are still meaningful, a brief statement about which one does what would also be helpful.