Let me start by saying that PortableApps Menu is the best looking portable menu I've seen so far. And I've tried dozens.
I do have a few suggestions.
1. Use config or ini files to build the menu instead of scanning for exe's.
You could load the app list from a central config on startup.
Then if the "Refresh App Icons" is pressed, scan for app config files (I notice the app/appinfo/appinfo.ini) and rebuild the central config from them.
If the "Install a New App" button is pressed have it browse for the exe, and build the app config file. (useful for "non_portableapps" apps)
2. Not related to portable apps, but if you have the time, I would like to see PortableApps Menu run from a customizable button rather that the systray. (I've been searching forever for a decent replacement for nu2menu for bartpe) I think the entire Portable Apps Suite would be fantastic for this.
3. An option to display the entire menu rather than scroll.
Again love the menu, I've already added almost every program on my usb drive (except the ones with multiple exe's)