Actually, it all depends on the coders who've coded the applications. Some apps are high-res aware while some are not. Some can be hacked to VGA mode(Eg:adobe reader 2.0). This is called MUI hack, which can be done by Tweaks2k2.net app
Most of the popular apps make use of high-resolution. eg: IE, Opera, Adobe reader LE, adobe reader 2.0(after MUI hack), SPB insight etc
PS: if you mention the app, then, I can take a look at it and tell you whether it can be forced into high-resolution mode