diff --git a/slider.lua b/slider.lua
index d540348..e14dc96 100644
--- a/slider.lua
+++ b/slider.lua
@@ -18,7 +18,7 @@ return function(core, info, ...)
 	if core:isActive(opt.id) then
 		-- mouse update
 		local mx,my = core:getMousePosition()
-		if opt.vertical then
+		if opt.id.vertical then
 			fraction = math.min(1, math.max(0, (y+h - my) / h))
 		else
 			fraction = math.min(1, math.max(0, (mx - x) / w))
@@ -30,8 +30,8 @@ return function(core, info, ...)
 		end
 
 		-- keyboard update
-		local key_up = opt.vertical and 'up' or 'right'
-		local key_down = opt.vertical and 'down' or 'left'
+		local key_up = opt.id.vertical and 'up' or 'right'
+		local key_down = opt.id.vertical and 'down' or 'left'
 		if core:getPressedKey() == key_up then
 			info.value = math.min(info.max, info.value + info.step)
 			value_changed = true
diff --git a/theme.lua b/theme.lua
index 7981c21..22f3ac9 100644
--- a/theme.lua
+++ b/theme.lua
@@ -83,7 +83,7 @@ end
 function theme.Slider(fraction, opt, x,y,w,h)
 	local xb, yb, wb, hb -- size of the progress bar
 	local r =  math.min(w,h) / 2.1
-	if opt.vertical then
+	if opt.id.vertical == true then
 		x, w = x + w*.25, w*.5
 		xb, yb, wb, hb = x, y+h*(1-fraction), w, h*fraction
 	else
@@ -97,7 +97,7 @@ function theme.Slider(fraction, opt, x,y,w,h)
 
 	if opt.state ~= nil and opt.state ~= "normal" then
 		love.graphics.setColor((opt.color and opt.color.active or {}).fg or theme.color.active.fg)
-		if opt.vertical then
+		if opt.id.vertical then
 			love.graphics.circle('fill', x+wb/2, yb, r)
 		else
 			love.graphics.circle('fill', x+wb, yb+hb/2, r)