Common properties

Most components accept the properties below. A component page lists them only when the component uses them.

Name	Type	Description
Theme	ThemeRef	Theme for this component, instead of the one from Theme.Provide. It can be a theme or a state of one.
LayoutOrder	UsedAs<number>	Position in a parent UIListLayout or UIGridLayout.
Size	UsedAs<UDim2>	Size. Each component has its own default.
Visible	UsedAs<boolean>	Whether the component is shown.
ZIndex	UsedAs<number>	Z index.
Layer	Instance	Where floating content is mounted. See Overlay layers.
Id	string	Names the component so it can find its state again after a rebuild. See Persisting state.

UsedAs<T>

UsedAs<T> is the Fusion type for a value that can be a T or a state that holds a T. A property of this type follows a state when you give one.

Values you can follow

A control that lets the user change a value, such as Checkbox, Switch, Slider, Select, Tabs, TextField and ColorPicker, keeps that value in its own state. What the property does depends on what you give it:

• A plain value, such as Checked = true, is the starting value. The control keeps its own state from then on.
• A Value is linked to the control in both directions. Setting the Value moves the control, and the user changing the control sets the Value.
• A Computed cannot be set, so it only moves the control. The control still changes when the user uses it, and the next change of the Computed overrides that.

local volume = scope:Value(40)

C.Slider(scope, { Min = 0, Max = 100, Value = volume })

volume:set(75) -- the slider moves

Use the callback of the component, which is OnChanged for most of them, when you want to run code on a change.

A control whose value you link this way is not kept across rebuilds, since you own that state.

Properties that are read once

Where a property is described as read once, changing the state later has no effect. Disabled is read once on most components.