Unable to modify/delete custom styles

If I have sheet protection enabled for any sheet in a document, style modification does not work as expected - even when a non-protected sheet is in focus. I can still pull up the style list and even get the right-click context menu item to modify the style but when attempted, the app does not present the style modification panel. I must first disable sheet protection on ALL sheets in the document and then I am able to modify styles as expected.

Is this normal?

Perhaps it is because styles are by file not by sheets.