XYplorer Beta Club

(Ctrl+Shift+G) opens "Go to from Here" and the text in input field will be selected
but using #532; will make mouse cursor be after backslash at the end (no selected text)
why this difference in behavior?

It is because keyboard modifiers are used when the dialog is invoked, you can test this by holding Shift down and using it from the Go menu. As a workaround if you want the select all behavior (and for some reason didn't want to just use plain GoTo) you could invoke it something like this:
or alternatively:

Thank you for this explanatory and workaround