Lines get a Border color, an easier click, and Select similar
A line has a Border color, not a Fill. Select a line and the toolbar now shows Border, with the line's color and its thickness. Before, it showed Fill like any shape, and on many lines, such as the rules from an imported document, changing it did nothing. The Border color you pick is the color the line is drawn in, on the slide and in exports. With several lines selected it changes all of them, and it leaves any boxes or circles in the selection alone.
Lines are easier to click. A thin line used to be a target a pixel or two tall, so the usual move was to drag a box around it. Every line now has a click area about ten pixels wide on screen, however far you are zoomed in or out. It makes no difference to how the line looks.
Select similar in the Select menu. Right-click a widget, open Select, and choose Select similar to pick everything that looks like it, even where the match is not exact. For a line, that is lines of a close color, about the same thickness and running the same way, whatever their length, which is how you grab the rules of an imported table in one go. For text it is the same font at a similar size and color. For shapes and pictures it is the same kind with a close color or the same proportions. The other Same rows in the menu still match exactly, and Only this slide applies to this one too.

