Why isn't this GUI bind working?

local screenGui = Instance.new("ScreenGui")
screenGui.Parent = script.Parent

local textLabel = Instance.new("TextLabel")
textLabel.Parent = screenGui
textLabel.Position = UDim2.new(0, 0, 0, 0)
textLabel.Size = UDim2.new(0, 200, 0, 180)
textLabel.BackgroundColor3 = BrickColor.Green().Color
textLabel.TextXAlignment = 0
textLabel.TextYAlignment = 0
textLabel.Font = 10
textLabel.FontSize = 5
textLabel.Text = ""
textLabel.Visible = false

local textBox = Instance.new("TextBox")
textBox.Parent = screenGui
textBox.Position = UDim2.new(0, 0, 0, 180)
textBox.Size = UDim2.new(0, 200, 0, 20)
textBox.BackgroundColor3 = BrickColor.Green().Color
textBox.TextXAlignment = 0
textBox.TextYAlignment = 1
textBox.Font = 10
textBox.FontSize = 5
textBox.Text = ""
textBox.Visible = false

function onKeyPress(inputObject, gameProcessedEvent)
    if inputObject.KeyCode == Enum.KeyCode.Tilde then
        textLabel.Visible = true
        textBox.Visible = true
    end
end
game:GetService("UserInputService").InputBegan:connect(onKeyPress)

Everything except for the final paragraph of code is working. Does anyone know what the problem is? Thank you!

EDIT: I've figured out that the tilde is actually the thing causing the problem, not the other commands.