I’m looking for opinions on this.
You have a Listbox with expandable rows. You click a disclosure widget while holding down a modifier key and all the rows expand (or collapse). Which modifier key do you use?
On the Mac, I’d use the option key, but what about the other platforms?
0 voters
shift and control have a select meaning at windows, shift is select from to and ctrl select single rows.
why not just use the rectangle area of the disclosure widget?
strg or alt is good for people having left hand on keyboard and using right hand for mouse.
or how about if mouse is over using space to open / close? or cursor down/up left/right.
something intuitive.
never double keys where you break your fingers.
Follow MS Guidelines for treeviews
Think this amounts to “its not a thing on Windows”
In my use case, it’s helpful, almost required, so I won’t read its absence in the text as “don’t do it”.
Thank you for the link.
Never said “dont do it”
Just that it’s not common at all on Windows so people, who often do not read manuals, wont find it unless they read the manual
Which a lot don’t do 
If its almost required you could either pre-open the whole tree or add expand/collapse all buttons/icons at the top
Or a contextual menu item.
my mouse have many extra buttons.
it is maybe also an option to map this buttons to keys with the tool came with mouse setup.
i can click the wheel or press it to left and right.
and at thumb i have two extra buttons.
or open/close voice input?
I should mention that this is for an open-source project, so there is also a limit on how much I want to put into it.
I’ve also seen Ctrl + RightArrow to open all and Ctrl + LeftArrow to close all.
That’s for an entirely keyboard-based solution, and I may implement that. I was looking for a modifier key in conjunction with a mouse-click here.
could u use a larger disclosure widget icon that the left open/close all and the right part open a single area?
or make a modifier key property (or enum) that it is flexible to use.
Alt key it is. Thank you all.