How to Clear This Dialog Box ?

Beats me - what do you mean

I tried to reproduce it but couldn't. How are you getting it to appear?

Also, what app are you using to open the files?

You seem to have the 'Open' dialog box open, those files in the list would be previously saved/opened files and the 'history' (or Most Recently Used files) will probably be controlled in whatever application you're using.


OS

that looks to me like the libraries music folder, you can change the view from the list,


and change the arrange by song to album and change the details view


Edit actually looking closer at the clip that looks like a search feature of some sort , Im with tw33k i cant replicate it and i havent seen it before.

This tells me it's an 'Open with' (or similar) dialog box



Pressing CTRL+O while in Media Player opens the same type of dialog box

If you want to selectively clear the Common Dialog file names MRU, you need to delete these two registry keys manually:

HKEY_CURRENT_USER \ Software \ Microsoft \ Windows \ CurrentVersion \ Explorer \ ComDlg32 \ LastVisitedPidlMRU

HKEY_CURRENT_USER \ Software \ Microsoft \ Windows \ CurrentVersion \ Explorer \ ComDlg32 \ OpenSavePidlMRU

Just tested it and it works :)