If you want to change the default delimiter for any other value, you can do it in one of the following two ways:
Click any column of the first row in the Record pane of the Metadata Editor. After that, there will appear record properties in the Details pane. Among them, there will be the Default delimiter property. Change this delimiter for any other value.
Such new value of default delimiter will appear in the rows of the Record pane where default delimiter has been used instead of the previous value of default delimiter. These values will again be displayed greyish.
Click the Delimiter column of the first row in the Record pane of the Metadata Editor. After that, you only need to replace the value of this cell by any other value.
Change this delimiter for any other value.
Such new value will appear both in the Default delimiter row of the Details pane and in the rows of the Record pane where default delimiter has been used instead of the previous value of such default delimiter. These values will again be displayed greyish.