ListBox Cell Edit “close” when DnD elsewhere…

Pretty cryptic title. A hard to create one. Here’s the logic:

I am doing copy / paste stuff from firefox or safari into a Xojo created application’s ListBox in Cell Edit Mode.

Once in a while I have to change the original html page and so I use drag an html file from the Finder and drop it into Safari (or Firefox) window.

I do not quit the Xojo application nor I press Return to close the Cell. edit mode

After that “external drag and drop”, the Cell Edit was closed by itself.

Not an annoyance, but a curiosity:

Is this an attended (standard) behavior ?