With a mouse

One-by-one: Click the widget you want to select. To select another, press and hold [ctrl] while you click to select more.

Region: Click and hold on empty surface space, and draw a rectangle. When you let go, all widgets touching the rectangle will be selected

Hold [alt] to move the rectangle around; Hold [ctrl] to create a new widget with the dimensions of the rectangle

Deselecting: Click once on empty surface space to deselect all widgets

With touch

Tap each widget you want to select. To deselect widgets, tap once on the surface

With searching

If you use the console search feature, pressing [enter] will select matching widget(s)