Sorry it is a little confusing, Ctrl+Shift+A is deselect all (or select none) which for the purposes of selection such as quick grouping or export etc is the same as select all. Confusing I know but I've just got used to it.
So if I need to select all for any reason I actually deselect all. The main reason I do that is a select all can appear to select everything but I've sometimes found only part of the time line selected for example which is quite hard to notice with selection.
Select none solved that for me and that's how I do it all the time now. Try it. Ctrl+Shift+A and then quick group, you'll see what I mean.
HTH