When I open a picture (or any other file type) on my Key2, I see the "Open with [app] Just Once/Always" pop-up.
I pick my preferred photo viewing (or whatever) app and press ALWAYS.
The next several times I open a picture (or whatever), it correctly opens in the selected app.
Some time later, perhaps the next day or perhaps the next week, when I open a picture (or whatever) of the same file type, I get the "Open with [app] Just Once/Always" pop-up again. Android keeps forgetting the default app I selected. I don't think I'm doing anything to trigger this amnesia (such as installing a new app of the same type or receiving an update to the selected app or taking any particular action to erase the association).
This has been going on for months, and it's getting old. Why do I have to keep telling Android which app to use? Why does it eventually (but not immediately) keep forgetting the app I selected? Shouldn't "always" mean "always" and not "just for the next little while"?
This can happen when a new app is installed and/or current ones are updated. This can also happen if you installed another of the same type and then deleted it. I don't believe it's Key² specific issue but on Android in general.
Note that sometimes when an app is updated, it has a new ability added to it. For eg, you've Firefox shown to open a photo, which clearly isn't a Photo viewer app.