That is because remove-overlays uses eq when testing an overlay-property's value. But two strings are only equal, if they are the same object.

Usually one adds a symbol-property with a constant value, usually t, in order to keep track of ones overlays.

That is because remove-overlays uses eq when testing an overlay-property's value. But two strings are only equal, if they are the same object.

Usually one adds a symbol property with a constant value, usually t, in order to keep track of one's overlays.