The file you have opened. Open via the File menu, the button marked 11, or by dragging-and-dropping on the list box 5. You'll get a message like "Nothing to display" if the program cannot open the file.
Disk selector. Starts from zero.
When reading in a disk, the sector data is concatenated and then compared to the track data via calculated CRCs. If the CRCs match, the disk is marked with a tick. If not, a cross. Place for up to 16 disks in a set - if there are more the extras will be ignored.
Note that a cross is not always a problem. Here is disk 7(6) in the set. It is the "User" disk and has not been fully formatted. Comparing the track data to the sector data thus gives errors, as the sector lengths are effectively zero:
Set size comparison. This compares the actual file size you opened, with the sum of the reported sizes off the headers, with the sum of the sizes of the concatenated sectors. If all equal, a tick is shown. If not, a cross.
This is not necessarily a problem. An example where all the disks look good, but the file length is funny - huh! - turns out there are a bunch of low-values ( H"00" ) appended at the back of the file which can be deleted with a hex editor with no harm done:
Information off the header of the selected disk and calculated CRCs. If the CRC excluding the header and the CRC of sectors match, then the disk is pretty well internally consistent. It might still be a bad dump though!
One thing to watch is that some multi-disk sets have the disks in different orders to other dumps.
Track info showing start of track, length, running total ( start plus length ), track number, and difference to calculated sum of reported sector lengths - see 3 above. If the track and sector data match, a tick is shown, else an asterisk or cross.
Hex view of the track data.
Hex view of the concatenated sectors. Should be the same as 7, but can vary. Might or might not be a problem. Again a User disk, with sector padded with H"00":
Press to show a hex dump of the disk header.
Press to highlight differences in the two hex displays, whatever their content, in different colours. See 8 above for pic.
Press to open file.
Length Info.
Superfluous pics.
I think one must always apply one's brain to any funnies, as not all funnies are problems.