Thank you raistlin2k for your suggestions.
1. if a file >2 GB gets added to an image, it should automatically switch to UDF DVD (disable ISO9660) or at least ask for that instead of burning an invalid DVD.(ISO9660 with files > 2GB)
As ISO9660 volume can hold files up to 4GB properly, UltraISO asks for switching to UDF DVD only if a file > 4GB is added.
2. It would be nice if the Filesystem properties for a new image right after startup of UltraISO could be set in the preferences of the program. For example: I prefer burning only with ISO9660 & UDF (and UDF only for DVD >2GB). So it would be nice if the user can preset the filesystem settings..
You can do it this way:
1) Choose 'File'->'Properties' from main menu
2) Check ONLY UDF
3) Click 'Set as default' button
Then UltraISO will work as you wanted.
3. Just a question: what's the use of the DVD Disc checkbox in the burning dialog window?
This is an option for NeroAPI, the next release of UltraISO will hide this option if it is not needed.