Right. What I asked was if 4.4.3.3 had the desired behavior or not. Looking at the code, I can see that it is quite likely that it has never done what you're requesting it do. You see, when you drop a photo on the application icon, it launches a new instance of Photo Mechanic which sees that another one already exists. ...
Sorry I was not clear. If PM is not running and I drop a selected Windows Explorer thumbnail or file name onto the PM desktop icon, I would expect PM to start running, position the contact sheet to the exact contact sheet thumbnail, select the thumbnail (and then display the preview). For example, Adobe Bridge and to a certain degree, even Windows Picture and Fax Viewer (which does not have a "contact sheet") work in this way. At present, PM will only open the directory as a contact sheet but NOT position to the dropped file.
The expectation is that a single file name is dropped onto the desktop icon - or that a single file name is added to the command line when PM would be executed and that file name would be used for processing. This is, as far as I can see, the operation of most programmes such as Microsoft Word, Notepad, and many other programmes. As another example, if you use the PM option of "Show In Windows Explorer", explorer will display the directory, position the directory to the (last) file selected, and select the (last) file. (I cannot comment on how apple systems work).
If multiple files are dropped onto the desktop icon (or if multiple file names are added to the command line execution) things can be confusing. In the case of Adobe Bridge, multiple instances of Bridge are invoked - one for each file name and the image is properly displayed on each of the preview screens. This multiple activation strategy seems to be operationally incorrect (IMO) for PM. I would think the best strategy would be to only open the first file on the command line, display the directory as a contact sheet, position the contact sheet to the file, select the file (and, preferably display the preview).
If a thumbnail from a PM contact sheet is drag-and-dropped onto the PM desktop icon, the present action of "do nothing" seems to be correct.
tony.