How to multi (SHIFT) select in Outliner window?

Hello,
I (still newbee) have several small cubes in my scene which are inside other objects and I want to select all small cubes at once to change their size at once.
The cubes are very difficult to select by the mouse because they are hidden by other objects.
So I tried to select them by the Outliner window.
But how can I multiselect the cubes? I only get one cube selected, even if I keep the SHIFT key pressed.

What I am doing wrong? (I use 2.42a)

Thanks for any help!

In 2.42a it’s shift LMB to multiselect in the outliner, if you have the default mouse settings. In 2.43RC1 it’s more consistent - you right-click to get a menu of options.