Open file via Drag & Drop not working on 1.1

I often open multiple files to play a set of them in sequence, and this is a convenient way to do that. I can select a group of files in explorer, and then drag that onto the Musescore window.

When I installed 1.1 for the first time on my primary desktop, I seemed to lose the ability to open files by drag&drop from Windows Explorer to the Musescore window. The cursor would never change from a circle with a slash through it when hovering over the desktop.

However, after a week or so, the drag&drop did start working.

I recently installed 1.1 onto another desktop computer and it, too, started refusing to accept files via drag&drop. I wonder if there is a setting I am missing.

OS: Windows 7
Musescore version 1.1 revision 4611
Sequence of steps:
1) open Musescore to an empty desktop
2) switch to Windows Explorer
3) highlight a selection of music files (*.mid or *.mscz files)
4) hold left mouse button, drag from explorer to the taskbar, hover over the Musescore taskbar button until Musescore window comes to the front of the desktop
5) still holding the left mouse button, move mouse over the Musescore window.

The desired behavior is that the cursor pointer would change to indicate I can now release the mouse button and open the set of files. The actual behavior is the cursor shape is a O with a slash through it, indicating an illegal operation.