Start work on plugin UI, this is pretty painful

plugin/src/Components/FitList.lua

@@ -0,0 +1,63 @@
+local Roact = require(script:FindFirstAncestor("Rojo").Roact)
+
+local e = Roact.createElement
+
+local function merge(...)
+	local output = {}
+
+	for i = 1, select("#", ...) do
+		local source = select(i, ...)
+
+		if source ~= nil then
+			for key, value in pairs(source) do
+				output[key] = value
+			end
+		end
+	end
+
+	return output
+end
+
+local FitList = Roact.Component:extend("FitList")
+
+function FitList:init()
+	self.sizeBinding, self.setSize = Roact.createBinding(UDim2.new())
+end
+
+function FitList:render()
+	local containerProps = self.props.containerProps
+	local layoutProps = self.props.layoutProps
+	local paddingProps = self.props.paddingProps
+
+	local padding
+	if paddingProps ~= nil then
+		padding = e("UIPadding", paddingProps)
+	end
+
+	local children = merge(self.props[Roact.Children], {
+		["$Layout"] = e("UIListLayout", merge({
+			SortOrder = Enum.SortOrder.LayoutOrder,
+			[Roact.Change.AbsoluteContentSize] = function(instance)
+				local size = instance.AbsoluteContentSize
+
+				if paddingProps ~= nil then
+					size = size + Vector2.new(
+						paddingProps.PaddingLeft.Offset + paddingProps.PaddingRight.Offset,
+						paddingProps.PaddingTop.Offset + paddingProps.PaddingBottom.Offset)
+				end
+
+				self.setSize(UDim2.new(0, size.X, 0, size.Y))
+			end,
+		}, layoutProps)),
+
+		["$Padding"] = padding,
+	})
+
+	local fullContainerProps = merge(containerProps, {
+		Size = self.sizeBinding,
+	})
+
+	return e("Frame", fullContainerProps, children)
+end
+
+return FitList