There appears to be a problem with the file association functionality in (at least) the 64 bit edition of the current RC under Windows 7. I have only just downloaded and installed the beta/RC, so I do not know whether the issue is new or just previously unreported.
After installing the program and opening (e.g.) a php file, I go to Tools|Properties for Current configuration. The tab that opens gives “Associated Extensions” as PHP and PHP3. However, clicking on files with these extensions in Explorer does not open them in EmEditor. Returning to the same tab in EmEditor and pressing the ‘Associate with EmEditor’ button pops up a UAC dialog, to which I respond appropriately, and I then see a new dialog box, showing only a txt association. Deleting this and adding appropriate php associations still does not affect Explorer’s behavior.
Even more strangely, Windows own File Association manager will not allow me to add the necessary associations. EmEditor is not shown as an option in the normal dialog (even by expanding ‘Other Programs”) and navigating the dialog to the program folder and ‘Opening’ EmEditor.exe neither associates it nor adds EmEditor to the available options.