Detection Method Query

Hi,

I have a scenario. I am installing an SCCM Application.

1) I have installed Firefox 1.0 on my machine.

2) On top of it, I have installed Firefox 2.0 ( No Supersedence used, Firefox 2.0 has internal logic to uninstall Firefox 1.0).

3) So after sometime, I found Firefox 1.0 getting installed back on my machine and sitting together with Firefox 2.0.

I was puzzled how it got re-installed. I had checked the AppDicovery.log and found below,

SCCM was checking the detection method and found Firefox 1.0 missing from the machine so it brought back the Firefox 1.0.

1) Does it mean I cannot use internal logic to uninstall previous versions ?

2) Let us suppose an Application has detection method to check file existence, C:\temp\A.txt.

If user accidentally deletes this file, will the whole application re-install on the user machine ?

Please advise.