egg:

My turn to repeat myself: the use of the ctrl modifiier in addiing to the selection of colours in the name gallery is redundant, it's irrelevant - a simple click does it: have you actually tried that?

the OP said, amongst other things:

Only being able to select one colour at a time is frankly painful
and that is exactly the situation, the selection process is one at a time

this is not the same thing as 'only being able to have one colour selected'
I'm well aware you misunderstood that post, easy to do if you don't read it carefully

And reading said post carefully you see that he has tried all the modifiers and they don't do what he wants - so why not start thinking outside the box?

which leads me to your:

What I've questioned is the use of such a function in a name gallery that has no structure other than to list arbitrary names in numerical order that Xara assigns (Unnamed colour 234 etc.)

For such a feature to be useful you would need to be able to list the colour name gallery by hue and Shift select between similar hues and change all the fills to a single hue.

say I import a traced vector file - if [and it's a big if] all the shapes have unique colour values, then the order in the name gallery is the inverse of the stacking order in the P&L gallery - I understand that this is because the program builds the object stack from the bottom up, listing out the name gallery entries as it goes along; in this special case it is possible to do what the OP wants using the P&L gallery... but in practice life is never that simple, colour values will be duplicated and, as they are, an entry in the name gallery will be 'missed out' as that value has already been covered

now what if this stack of objects represents more than one 'thing' and we need to seperate them out? and the objects that make up each 'thing' are not contiguous within the stack? and, furthermore, the 'things' are not monochromatic and so organising name gallery by hue/saturation/value would not necessarily be of use; might be if each 'thing' had a unique palette, but that would be asking to much as well

there may be hundreds/thousands of these objects, too many to sort out directly in the work space [as the OP said] because you cannot see what you are doing being either zoomed too far out or too far in, so what do you do to seperate them out?

and we should not forget that there could be more than one 'stack' interwoven in the layer - sets within sets

these are often very compliocated patterns, but they are not 'willy-nilly' - seperating them out is seat-of-the-pants - like taking apart a jigsaw puzzle that has been put together wrong, and looking for something that starts to mean something, so unless you know what you are looking for, no it won't make any sense....

thats probably enough for one post...

[For all I know the OP does something different - but this is what I used to do - would often have been easier if xara had imported proper nested layer structures instead of bunching it all together, but there ya go]