Since updating to 5.1 b1913 (W7x64) today, I find all my jpgs now open with the native MC viewer, (I have been using irfanview normally as it has a bit more functionality) but despite resetting the default app for the jpg ext I cannot directly open them with irfanview any more. Always uses the MC viewer unless I right click/open with.
I haven't rebooted the PC yet but I thought I better mention it...
Change Log
CHANGE- FileType Default setup change to use Internal Picture viewer when "open/run" a images file.
(If you have done any changes to the FileType setup before, you will not get this behavior. You only get it if you are running the unmodified defaults)
A lot of uses have complain that the viewer is not used when they double click on files. "MC suppose to have a built in viewer.. why does it not show my image when I click on it"
Answer is Because because clicking it will call for the open/Run action and not the view action. But for most uses there is no difference.
So because of that I added that the default file type setup include an entry to use internal viewer for picture files for Run/Open action.
Menu > Configuration > File Type Setup > Launchers (Run/Open) tab
Remove the "MC Picture Viewer" row in that tab and what ever windows has associated will not be used again..
I'm not sure I will keep this behavior as default. Maybe depends on what sides complains more.
Problem is that it hides the associated 3de party program (like you noticed). But if you do not have that installed you will now get the internal viewer.