Can't drag-and-drop file into TP

[VSLEWIS]

I am having trouble drag-and-drop files from "File Explorer" into TP.
When I try to "drag-and-drop" a file: when the cursor scope is within the TP window it changes to a "plus" sign (adding file) and after I release the mouse
the cursor changes back to default but the file is not opened!

Does TP not have "drag-and-drop"?

[AmigoJack]

It does, no matter where your mouse cursor resides (can be any portion of any window of TextPad).

Make sure TextPad has actually read access to the file you want to drop (how? Use the File > Open dialog). Make sure other programs still support drag'n'drop (i.e. Notepad).