It's possible by changing the file associations in the Registry, e.g. to Notepad++
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\.ta]
@="TestAdoreTest"
[HKEY_CLASSES_ROOT\TestAdoreTest]
@="TestAdore Test Case"
[HKEY_CLASSES_ROOT\TestAdoreTest\shell]
[HKEY_CLASSES_ROOT\TestAdoreTest\shell\open]
[HKEY_CLASSES_ROOT\TestAdoreTest\shell\open\command]
@="\"C:\\Program Files (x86)\\Notepad++\\notepad++.exe\" \"%1\""
I found it convenient to have another entry in the context menu to be able to run them:
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\TestAdoreTest\shell\exec]
@="Run with TestAdore Performer"
[HKEY_CLASSES_ROOT\TestAdoreTest\shell\exec\command]
@="\"C:\\Program Files (x86)\\WelliSolutions\\TestAdore\\PerformerXml.exe\" \"%1\""