In the wake of this me tempering with the Tag Panel [Tag Panel Rows configuration] I came to the obvious conclusion
It would be user friendly if under the
Tool > Options > Tag Panel
there was an Apply button, that would implement the changes done to the Tag Panel without the need of leaving that Mp3tag Options window. And / or the same button could be also available in every Edit field... sub-window, that pop up when we edit a given field of the Tag Panel
Because this way the changes would be visible right away and since the Tag Panel became more configurable than ever [with all those sizes of fields and number of rows], this would speed up a configuration process. This way such new button would also not interfere with other configurable options, as there are many of them in the Tool > Options [and I suspect that it might be the reason why there is no such button yet at the very bottom of the Mp3tag Options window, right next to the OK, Cancel and Help buttons]