diff --git a/src/kits/interface/ControlLook.cpp b/src/kits/interface/ControlLook.cpp
index 6af0612928..0c13e18c2c 100644
--- a/src/kits/interface/ControlLook.cpp
+++ b/src/kits/interface/ControlLook.cpp
@@ -889,10 +889,11 @@ BControlLook::DrawSliderBar(BView* view, BRect rect, const BRect& updateRect,
 		leftBarSide.right = sliderPosition - 1;
 		rightBarSide.left = sliderPosition;
 	} else {
+		// NOTE: position is reverse of coords
 		sliderPosition = floorf(rect.top + 2 + (rect.Height() - 2)
-			* sliderScale);
-		leftBarSide.bottom = sliderPosition - 1;
-		rightBarSide.top = sliderPosition;
+			* (1.0 - sliderScale));
+		leftBarSide.top = sliderPosition;
+		rightBarSide.bottom = sliderPosition - 1;
 	}
 
 	// fill the background for the corners, exclude the middle bar for now
@@ -1223,14 +1224,23 @@ BControlLook::DrawSliderTriangle(BView* view, BRect& rect,
 	view->SetFlags(viewFlags | B_SUBPIXEL_PRECISE);
 	view->SetLineMode(B_ROUND_CAP, B_ROUND_JOIN);
 
-	float center = (rect.left + rect.right) / 2;
+	float centerh = (rect.left + rect.right) / 2;
+	float centerv = (rect.top + rect.bottom) / 2;
 
 	BShape shape;
-	shape.MoveTo(BPoint(rect.left + 0.5, rect.bottom + 0.5));
-	shape.LineTo(BPoint(rect.right + 0.5, rect.bottom + 0.5));
-	shape.LineTo(BPoint(rect.right + 0.5, rect.bottom - 1 + 0.5));
-	shape.LineTo(BPoint(center + 0.5, rect.top + 0.5));
-	shape.LineTo(BPoint(rect.left + 0.5, rect.bottom - 1 + 0.5));
+	if (orientation == B_HORIZONTAL) {
+		shape.MoveTo(BPoint(rect.left + 0.5, rect.bottom + 0.5));
+		shape.LineTo(BPoint(rect.right + 0.5, rect.bottom + 0.5));
+		shape.LineTo(BPoint(rect.right + 0.5, rect.bottom - 1 + 0.5));
+		shape.LineTo(BPoint(centerh + 0.5, rect.top + 0.5));
+		shape.LineTo(BPoint(rect.left + 0.5, rect.bottom - 1 + 0.5));
+	} else {
+		shape.MoveTo(BPoint(rect.right + 0.5, rect.top + 0.5));
+		shape.LineTo(BPoint(rect.right + 0.5, rect.bottom + 0.5));
+		shape.LineTo(BPoint(rect.right - 1 + 0.5, rect.bottom + 0.5));
+		shape.LineTo(BPoint(rect.left + 0.5, centerv + 0.5));
+		shape.LineTo(BPoint(rect.right - 1 + 0.5, rect.top + 0.5));
+	}
 	shape.Close();
 
 	view->MovePenTo(BPoint(1, 1));
@@ -1247,9 +1257,15 @@ BControlLook::DrawSliderTriangle(BView* view, BRect& rect,
 
 	rect.InsetBy(1, 1);
 	shape.Clear();
-	shape.MoveTo(BPoint(rect.left, rect.bottom + 1));
-	shape.LineTo(BPoint(rect.right + 1, rect.bottom + 1));
-	shape.LineTo(BPoint(center + 0.5, rect.top));
+	if (orientation == B_HORIZONTAL) {
+		shape.MoveTo(BPoint(rect.left, rect.bottom + 1));
+		shape.LineTo(BPoint(rect.right + 1, rect.bottom + 1));
+		shape.LineTo(BPoint(centerh + 0.5, rect.top));
+	} else {
+		shape.MoveTo(BPoint(rect.right + 1, rect.top));
+		shape.LineTo(BPoint(rect.right + 1, rect.bottom + 1));
+		shape.LineTo(BPoint(rect.left, centerv + 0.5));
+	}
 	shape.Close();
 
 	BGradientLinear gradient;
diff --git a/src/kits/interface/Slider.cpp b/src/kits/interface/Slider.cpp
index 7c685c7602..0509f1d525 100644
--- a/src/kits/interface/Slider.cpp
+++ b/src/kits/interface/Slider.cpp
@@ -703,16 +703,15 @@ BSlider::SetValue(int32 value)
 	if (fOrientation == B_HORIZONTAL)
 		oldThumbFrame.top = BarFrame().top;
 	else
-		oldThumbFrame.right = BarFrame().right;
+		oldThumbFrame.left = BarFrame().left;
 
 	BControl::SetValueNoUpdate(value);
 	BRect invalid = oldThumbFrame | ThumbFrame();
 
 	if (Style() == B_TRIANGLE_THUMB) {
-		// 1) we need to take care of pixels touched because of
-		//    anti-aliasing
-		// 2) we need to update the region with the focus mark as well
-		//    (a method BSlider::FocusMarkFrame() would be nice as well)
+		// 1) We need to take care of pixels touched because of anti-aliasing.
+		// 2) We need to update the region with the focus mark as well. (A
+		// method BSlider::FocusMarkFrame() would be nice as well.)
 		if (fOrientation == B_HORIZONTAL) {
 			if (IsFocus())
 				invalid.bottom += 2;
@@ -1445,16 +1444,27 @@ BSlider::GetPreferredSize(float* _width, float* _height)
 {
 	BSize preferredSize = PreferredSize();
 
-	if (_width) {
-//		*_width = preferredSize.width;
-		// NOTE: For compatibility reasons, the BSlider never shrinks
-		// horizontally. This only affects applications which do not
-		// use the new layout system.
-		*_width = max_c(Bounds().Width(), preferredSize.width);
-	}
+	if (Orientation() == B_HORIZONTAL) {
+		if (_width != NULL) {
+			// NOTE: For compatibility reasons, a horizontal BSlider
+			// never shrinks horizontally. This only affects applications
+			// which do not use the new layout system.
+			*_width = max_c(Bounds().Width(), preferredSize.width);
+		}
 
-	if (_height)
-		*_height = preferredSize.height;
+		if (_height != NULL)
+			*_height = preferredSize.height;
+	} else {
+		if (_width != NULL)
+			*_width = preferredSize.width;
+
+		if (_height != NULL) {
+			// NOTE: Similarly, a vertical BSlider never shrinks
+			// vertically. This only affects applications which do not
+			// use the new layout system.
+			*_height = max_c(Bounds().Height(), preferredSize.height);
+		}
+	}
 }