diff --git a/include/math.hpp b/include/math.hpp
index 617f01b3..1e4a9e55 100644
--- a/include/math.hpp
+++ b/include/math.hpp
@@ -184,6 +184,18 @@ struct Vec {
 	Vec() {}
 	Vec(float x, float y) : x(x), y(y) {}
 
+	float get(int index) const {
+		return (index == 0) ? x : y;
+	}
+	float& get(int index) {
+		return (index == 0) ? x : y;
+	}
+	void set(int index, float value) {
+		if (index == 0)
+			x = value;
+		else
+			y = value;
+	}
 	/** Negates the vector.
 	Equivalent to a reflection across the `y = -x` line.
 	*/
diff --git a/include/ui/ScrollBar.hpp b/include/ui/ScrollBar.hpp
index daa3d1b4..94786320 100644
--- a/include/ui/ScrollBar.hpp
+++ b/include/ui/ScrollBar.hpp
@@ -9,19 +9,17 @@ namespace ui {
 
 /** Parent must be a ScrollWidget */
 struct ScrollBar : widget::OpaqueWidget {
-	enum Orientation {
-		VERTICAL,
-		HORIZONTAL
-	};
-	Orientation orientation;
-	float offset = 0.0;
-	float size = 0.0;
+	struct Internal;
+	Internal* internal;
+
+	bool vertical = false;
 
 	ScrollBar();
+	~ScrollBar();
 	void draw(const DrawArgs& args) override;
 	void onDragStart(const event::DragStart& e) override;
-	void onDragMove(const event::DragMove& e) override;
 	void onDragEnd(const event::DragEnd& e) override;
+	void onDragMove(const event::DragMove& e) override;
 };
 
 
diff --git a/include/ui/ScrollWidget.hpp b/include/ui/ScrollWidget.hpp
index 48fb147c..f6e345d0 100644
--- a/include/ui/ScrollWidget.hpp
+++ b/include/ui/ScrollWidget.hpp
@@ -10,10 +10,15 @@ namespace ui {
 
 /** Handles a container with ScrollBar */
 struct ScrollWidget : widget::OpaqueWidget {
+	struct Internal;
+	Internal* internal;
+
 	widget::Widget* container;
 	ScrollBar* horizontalScrollBar;
 	ScrollBar* verticalScrollBar;
+
 	math::Vec offset;
+	math::Rect containerBox;
 
 	ScrollWidget();
 	void scrollTo(math::Rect r);
diff --git a/include/widget/Widget.hpp b/include/widget/Widget.hpp
index 64135dda..0e5a37ef 100644
--- a/include/widget/Widget.hpp
+++ b/include/widget/Widget.hpp
@@ -33,23 +33,21 @@ struct Widget {
 
 	virtual ~Widget();
 
+	math::Rect getBox();
 	void setBox(math::Rect box);
-	math::Rect getBox() {
-		return box;
-	}
+	math::Vec getPosition();
 	void setPosition(math::Vec pos);
-	math::Vec getPosition() {
-		return box.pos;
-	}
+	math::Vec getSize();
 	void setSize(math::Vec size);
-	math::Vec getSize() {
-		return box.size;
+	bool isVisible();
+	void setVisible(bool visible);
+	void show() {
+		setVisible(true);
 	}
-	void show();
-	void hide();
-	bool isVisible() {
-		return visible;
+	void hide() {
+		setVisible(false);
 	}
+
 	void requestDelete();
 
 	virtual math::Rect getChildrenBoundingBox();
diff --git a/src/ui/ScrollBar.cpp b/src/ui/ScrollBar.cpp
index fa342132..7c2ac64b 100644
--- a/src/ui/ScrollBar.cpp
+++ b/src/ui/ScrollBar.cpp
@@ -8,40 +8,63 @@ namespace rack {
 namespace ui {
 
 
+// Internal not currently used
+
+
 ScrollBar::ScrollBar() {
 	box.size = math::Vec(BND_SCROLLBAR_WIDTH, BND_SCROLLBAR_HEIGHT);
 }
 
+
+ScrollBar::~ScrollBar() {
+}
+
+
 void ScrollBar::draw(const DrawArgs& args) {
+	ScrollWidget* sw = dynamic_cast<ScrollWidget*>(parent);
+	assert(sw);
+
 	BNDwidgetState state = BND_DEFAULT;
-	if (APP->event->hoveredWidget == this)
+	if (APP->event->getHoveredWidget() == this)
 		state = BND_HOVER;
-	if (APP->event->draggedWidget == this)
+	if (APP->event->getDraggedWidget() == this)
 		state = BND_ACTIVE;
 
-	bndScrollBar(args.vg, 0.0, 0.0, box.size.x, box.size.y, state, offset, size);
+	float offsetBound = sw->containerBox.size.get(vertical) - sw->box.size.get(vertical);
+	// The handle position relative to the scrollbar. [0, 1]
+	float scrollBarOffset = (sw->offset.get(vertical) - sw->containerBox.pos.get(vertical)) / offsetBound;
+	// The handle size relative to the scrollbar. [0, 1]
+	float scrollBarSize = sw->box.size.get(vertical) / sw->containerBox.size.get(vertical);
+	bndScrollBar(args.vg, 0.0, 0.0, box.size.x, box.size.y, state, scrollBarOffset, scrollBarSize);
 }
 
+
 void ScrollBar::onDragStart(const event::DragStart& e) {
-	if (e.button != GLFW_MOUSE_BUTTON_LEFT)
-		return;
+	if (e.button == GLFW_MOUSE_BUTTON_LEFT) {
+		APP->window->cursorLock();
+	}
+}
+
 
-	APP->window->cursorLock();
+void ScrollBar::onDragEnd(const event::DragEnd& e) {
+	if (e.button == GLFW_MOUSE_BUTTON_LEFT) {
+		APP->window->cursorUnlock();
+	}
 }
 
+
 void ScrollBar::onDragMove(const event::DragMove& e) {
-	const float sensitivity = 1.f;
+	ScrollWidget* sw = dynamic_cast<ScrollWidget*>(parent);
+	assert(sw);
 
-	ScrollWidget* scrollWidget = dynamic_cast<ScrollWidget*>(parent);
-	assert(scrollWidget);
-	if (orientation == HORIZONTAL)
-		scrollWidget->offset.x += sensitivity * e.mouseDelta.x;
-	else
-		scrollWidget->offset.y += sensitivity * e.mouseDelta.y;
-}
+	// TODO
+	// float offsetBound = sw->containerBox.size.get(vertical) - sw->box.size.get(vertical);
+	// float scrollBarSize = sw->box.size.get(vertical) / sw->containerBox.size.get(vertical);
 
-void ScrollBar::onDragEnd(const event::DragEnd& e) {
-	APP->window->cursorUnlock();
+	const float sensitivity = 1.f;
+	float offsetDelta = e.mouseDelta.get(vertical);
+	offsetDelta *= sensitivity;
+	sw->offset.get(vertical) += offsetDelta;
 }
 
 
diff --git a/src/ui/ScrollWidget.cpp b/src/ui/ScrollWidget.cpp
index c9fc3d2a..9b7c08a3 100644
--- a/src/ui/ScrollWidget.cpp
+++ b/src/ui/ScrollWidget.cpp
@@ -6,37 +6,43 @@ namespace rack {
 namespace ui {
 
 
+// Internal not currently used
+
+
 ScrollWidget::ScrollWidget() {
 	container = new widget::Widget;
 	addChild(container);
 
 	horizontalScrollBar = new ScrollBar;
-	horizontalScrollBar->orientation = ScrollBar::HORIZONTAL;
-	horizontalScrollBar->visible = false;
+	horizontalScrollBar->vertical = false;
+	horizontalScrollBar->hide();
 	addChild(horizontalScrollBar);
 
 	verticalScrollBar = new ScrollBar;
-	verticalScrollBar->orientation = ScrollBar::VERTICAL;
-	verticalScrollBar->visible = false;
+	verticalScrollBar->vertical = true;
+	verticalScrollBar->hide();
 	addChild(verticalScrollBar);
 }
 
+
 void ScrollWidget::scrollTo(math::Rect r) {
 	math::Rect bound = math::Rect::fromMinMax(r.getBottomRight().minus(box.size), r.pos);
 	offset = offset.clampSafe(bound);
 }
 
+
 void ScrollWidget::draw(const DrawArgs& args) {
 	nvgScissor(args.vg, RECT_ARGS(args.clipBox));
 	Widget::draw(args);
 	nvgResetScissor(args.vg);
 }
 
+
 void ScrollWidget::step() {
 	Widget::step();
 
 	// Clamp scroll offset
-	math::Rect containerBox = container->getChildrenBoundingBox();
+	containerBox = container->getChildrenBoundingBox();
 	math::Rect offsetBounds = containerBox;
 	offsetBounds.size = offsetBounds.size.minus(box.size);
 	offset = offset.clamp(offsetBounds);
@@ -44,25 +50,19 @@ void ScrollWidget::step() {
 	// Update the container's position from the offset
 	container->box.pos = offset.neg().round();
 
-	// Update scrollbar offsets and sizes
-	math::Vec scrollbarOffset = offset.minus(containerBox.pos).div(offsetBounds.size);
-	math::Vec scrollbarSize = box.size.div(containerBox.size);
-
-	horizontalScrollBar->visible = (0.0 < scrollbarSize.x && scrollbarSize.x < 1.0);
-	verticalScrollBar->visible = (0.0 < scrollbarSize.y && scrollbarSize.y < 1.0);
-	horizontalScrollBar->offset = scrollbarOffset.x;
-	verticalScrollBar->offset = scrollbarOffset.y;
-	horizontalScrollBar->size = scrollbarSize.x;
-	verticalScrollBar->size = scrollbarSize.y;
+	// Make scrollbars visible only if there is a positive range to scroll.
+	horizontalScrollBar->setVisible(offsetBounds.size.x > 0.f);
+	verticalScrollBar->setVisible(offsetBounds.size.y > 0.f);
 
 	// Reposition and resize scroll bars
 	math::Vec inner = box.size.minus(math::Vec(verticalScrollBar->box.size.x, horizontalScrollBar->box.size.y));
 	horizontalScrollBar->box.pos.y = inner.y;
 	verticalScrollBar->box.pos.x = inner.x;
-	horizontalScrollBar->box.size.x = verticalScrollBar->visible ? inner.x : box.size.x;
-	verticalScrollBar->box.size.y = horizontalScrollBar->visible ? inner.y : box.size.y;
+	horizontalScrollBar->box.size.x = verticalScrollBar->isVisible() ? inner.x : box.size.x;
+	verticalScrollBar->box.size.y = horizontalScrollBar->isVisible() ? inner.y : box.size.y;
 }
 
+
 void ScrollWidget::onButton(const event::Button& e) {
 	OpaqueWidget::onButton(e);
 	if (e.isConsumed())
@@ -77,12 +77,14 @@ void ScrollWidget::onButton(const event::Button& e) {
 	}
 }
 
+
 void ScrollWidget::onDragStart(const event::DragStart& e) {
 	if (e.button == GLFW_MOUSE_BUTTON_LEFT || e.button == GLFW_MOUSE_BUTTON_MIDDLE) {
 		e.consume(this);
 	}
 }
 
+
 void ScrollWidget::onDragMove(const event::DragMove& e) {
 	// Scroll only if the scrollbars are visible
 	if (!(horizontalScrollBar->visible || verticalScrollBar->visible))
@@ -91,6 +93,7 @@ void ScrollWidget::onDragMove(const event::DragMove& e) {
 	offset = offset.minus(e.mouseDelta);
 }
 
+
 void ScrollWidget::onHoverScroll(const event::HoverScroll& e) {
 	OpaqueWidget::onHoverScroll(e);
 	if (e.isConsumed())
@@ -112,6 +115,7 @@ void ScrollWidget::onHoverScroll(const event::HoverScroll& e) {
 	e.consume(this);
 }
 
+
 void ScrollWidget::onHoverKey(const event::HoverKey& e) {
 	OpaqueWidget::onHoverKey(e);
 	if (e.isConsumed())
diff --git a/src/widget/Widget.cpp b/src/widget/Widget.cpp
index d69e2904..35d4f089 100644
--- a/src/widget/Widget.cpp
+++ b/src/widget/Widget.cpp
@@ -14,11 +14,23 @@ Widget::~Widget() {
 	clearChildren();
 }
 
+
+math::Rect Widget::getBox() {
+	return box;
+}
+
+
 void Widget::setBox(math::Rect box) {
 	setPosition(box.pos);
 	setSize(box.size);
 }
 
+
+math::Vec Widget::getPosition() {
+	return box.pos;
+}
+
+
 void Widget::setPosition(math::Vec pos) {
 	if (pos.isEqual(box.pos))
 		return;
@@ -28,6 +40,12 @@ void Widget::setPosition(math::Vec pos) {
 	onReposition(eReposition);
 }
 
+
+math::Vec Widget::getSize() {
+	return box.size;
+}
+
+
 void Widget::setSize(math::Vec size) {
 	if (size.isEqual(box.size))
 		return;
@@ -37,28 +55,34 @@ void Widget::setSize(math::Vec size) {
 	onResize(eResize);
 }
 
-void Widget::show() {
-	if (visible)
-		return;
-	visible = true;
-	// Trigger Show event
-	event::Show eShow;
-	onShow(eShow);
+
+bool Widget::isVisible() {
+	return visible;
 }
 
-void Widget::hide() {
-	if (!visible)
+
+void Widget::setVisible(bool visible) {
+	if (visible == this->visible)
 		return;
-	visible = false;
-	// Trigger Hide event
-	event::Hide eHide;
-	onHide(eHide);
+	this->visible = visible;
+	if (visible) {
+		// Trigger Show event
+		event::Show eShow;
+		onShow(eShow);
+	}
+	else {
+		// Trigger Hide event
+		event::Hide eHide;
+		onHide(eHide);
+	}
 }
 
+
 void Widget::requestDelete() {
 	requestedDelete = true;
 }
 
+
 math::Rect Widget::getChildrenBoundingBox() {
 	math::Vec min = math::Vec(INFINITY, INFINITY);
 	math::Vec max = math::Vec(-INFINITY, -INFINITY);
@@ -71,6 +95,7 @@ math::Rect Widget::getChildrenBoundingBox() {
 	return math::Rect::fromMinMax(min, max);
 }
 
+
 math::Vec Widget::getRelativeOffset(math::Vec v, Widget* relative) {
 	if (this == relative) {
 		return v;
@@ -82,6 +107,7 @@ math::Vec Widget::getRelativeOffset(math::Vec v, Widget* relative) {
 	return v;
 }
 
+
 math::Rect Widget::getViewport(math::Rect r) {
 	math::Rect bound;
 	if (parent) {
@@ -94,6 +120,7 @@ math::Rect Widget::getViewport(math::Rect r) {
 	return r.clamp(bound);
 }
 
+
 void Widget::addChild(Widget* child) {
 	assert(child);
 	assert(!child->parent);
@@ -104,6 +131,7 @@ void Widget::addChild(Widget* child) {
 	child->onAdd(eAdd);
 }
 
+
 void Widget::addChildBottom(Widget* child) {
 	assert(child);
 	assert(!child->parent);
@@ -114,6 +142,7 @@ void Widget::addChildBottom(Widget* child) {
 	child->onAdd(eAdd);
 }
 
+
 void Widget::removeChild(Widget* child) {
 	assert(child);
 	// Make sure `this` is the child's parent
@@ -131,6 +160,7 @@ void Widget::removeChild(Widget* child) {
 	child->parent = NULL;
 }
 
+
 void Widget::clearChildren() {
 	for (Widget* child : children) {
 		// Trigger Remove event
@@ -143,6 +173,7 @@ void Widget::clearChildren() {
 	children.clear();
 }
 
+
 void Widget::step() {
 	for (auto it = children.begin(); it != children.end();) {
 		Widget* child = *it;
@@ -163,6 +194,7 @@ void Widget::step() {
 	}
 }
 
+
 void Widget::draw(const DrawArgs& args) {
 	// Iterate children
 	for (Widget* child : children) {