Vertical layout stub

backends/x/window.go

@@ -87,6 +87,12 @@ func (window *Window) Adopt (child tomo.Element) {
 			MinimumSizeChange: window.childMinimumSizeChangeCallback,
 			SelectionRequest: window.childSelectionRequestCallback,
 		})
+		// TODO: it is possible for an element to start out as
+		// selectable, and then become unselectable. it should be
+		// standard behavior for containers (including windows) to, if
+		// no children are selected, select the first child on ctrl-tab
+		// press. we should therefore be able to ask any element if it
+		// is selected.
 		if child.Selectable() { child.Handle(tomo.EventSelect { }) }
 		window.resizeChildToFit()
 	}

elements/layouts/vertical.go

@@ -0,0 +1,13 @@
+package layouts
+
+import "git.tebibyte.media/sashakoshka/tomo"
+import "git.tebibyte.media/sashakoshka/tomo/artist"
+
+// Vertical lays its children out vertically. It can contain any number of
+// children. When an child is added to the layout, it can either be set to
+// contract to its minimum height or expand to fill the remaining space (space
+// that is not taken up by other children or padding is divided equally among
+// these). Child elements will all have the same width.
+type Vertical struct {
+	
+}