diff --git a/button.go b/button.go
index 3ed6655..94aec44 100644
--- a/button.go
+++ b/button.go
@@ -12,6 +12,9 @@ var iconButtonLayout = layouts.Row { true        }
 var bothButtonLayout = layouts.Row { false, true }
 
 // Button is a clickable button.
+//
+// Tags:
+//   - [icon] The button has an icon.
 type Button struct {
 	box tomo.ContainerBox
 
diff --git a/calendar.go b/calendar.go
index a6739ee..f5ebda0 100644
--- a/calendar.go
+++ b/calendar.go
@@ -10,6 +10,16 @@ var _ tomo.Object = new(Calendar)
 
 // Calendar is an object that can display a date and allow the user to change
 // it. It can display one month at a time.
+// 
+// Sub-components:
+//   - CalendarGrid organizes the days into a grid.
+//   - CalendarWeekdayHeader appears at the top of each grid column, and shows
+//     the day of the week that column represents.
+//   - CalendarDay appears within the grid for each day of the current month.
+//
+// CalendarDay tags:
+//   - [weekend] The day is a weekend.
+//   - [weekday] The day is a weekday.
 type Calendar struct {
 	box tomo.ContainerBox
 	
diff --git a/checkbox.go b/checkbox.go
index e8ffacd..47b9725 100644
--- a/checkbox.go
+++ b/checkbox.go
@@ -7,6 +7,10 @@ import "git.tebibyte.media/tomo/tomo/event"
 var _ tomo.Object = new(Checkbox)
 
 // Checkbox is a control that can be toggled.
+//
+// Tags:
+//   - [checked] The checkbox's value is true.
+//   - [unchecked] The checkbox's value is false.
 type Checkbox struct {
 	box tomo.Box
 	value bool
diff --git a/colorpicker.go b/colorpicker.go
index fc452ee..a848e3d 100644
--- a/colorpicker.go
+++ b/colorpicker.go
@@ -12,6 +12,10 @@ var _ tomo.Object = new(HSVAColorPicker)
 
 // HSVAColorPicker allows the user to pick a color by controlling its HSVA
 // parameters.
+//
+// Sub-components:
+//   - ColorPickerMap is a recangular control where the X axis controls
+//     saturation and the Y axis controls value.
 type HSVAColorPicker struct {
 	box tomo.ContainerBox
 	value internal.HSVA
diff --git a/container.go b/container.go
index 93dadc5..5b75025 100644
--- a/container.go
+++ b/container.go
@@ -10,9 +10,14 @@ var _ tomo.ContentObject = new(Container)
 // primitive for building more complex layouts. It has two main variants: an
 // outer container, and an inner container. The outer container has padding
 // around its edges, whereas the inner container does not. It also has a
-// "sunken" variation designed to hold a scrolled list of items. The container
-// will have a corresponding object role variation of either "outer", "inner",
-// or "sunken".
+// "sunken" variation designed to hold a scrolled list of items.
+//
+// Tags:
+//   - [outer] The container is the root of a window.
+//   - [inner] The container is within another container, and is part of a
+//     larger layout.
+//   - [sunken] The container holds a visually grouped, usually scrolled, list
+//     of items.
 type Container struct {
 	box tomo.ContainerBox
 }
diff --git a/heading.go b/heading.go
index 6610027..3b42784 100644
--- a/heading.go
+++ b/heading.go
@@ -9,7 +9,12 @@ var _ tomo.Object = new(Heading)
 
 // Heading is a label that denotes the start of some section of content. It can
 // have a level from 0 to 2, with 0 being the most prominent and 2 being the
-// most subtle. The level is described in the role variation.
+// most subtle.
+//
+// Tags:
+//   - [0] The heading has a level of 0 (most prominent).
+//   - [1] The heading has a level of 1.
+//   - [2] The heading has a level of 2 (least prominent).
 type Heading struct {
 	box tomo.TextBox
 }
diff --git a/icon.go b/icon.go
index c3a2a70..aa152bf 100644
--- a/icon.go
+++ b/icon.go
@@ -6,6 +6,11 @@ import "git.tebibyte.media/tomo/tomo/canvas"
 var _ tomo.Object = new(Icon)
 
 // Icon displays a single icon.
+//
+// Tags:
+//   - [large] The icon is large sized.
+//   - [medium] The icon is medium sized.
+//   - [small] The icon is small sized.
 type Icon struct {
 	box  tomo.Box
 	icon tomo.Icon
diff --git a/menu.go b/menu.go
index 19db5ce..09957e0 100644
--- a/menu.go
+++ b/menu.go
@@ -7,6 +7,10 @@ import "git.tebibyte.media/tomo/tomo/input"
 import "git.tebibyte.media/tomo/objects/layouts"
 
 // Menu is a menu window.
+//
+// Sub-components:
+//   - TearLine is a horizontal line at the top of the menu that, when clicked,
+//     causes the menu to be "torn off" into a movable window.
 type Menu struct {
 	tomo.Window
 
diff --git a/scrollbar.go b/scrollbar.go
index 1a78742..2e6202d 100644
--- a/scrollbar.go
+++ b/scrollbar.go
@@ -9,6 +9,17 @@ var _ tomo.Object = new(Scrollbar)
 
 // Scrollbar is a special type of slider that can control the scroll of any
 // overflowing ContainerObject.
+//
+// Sub-components:
+//   - ScrollbarHandle is the grabbable handle of the scrollbar.
+//
+// Tags:
+//   - [vertical] The scrollbar is oriented vertically.
+//   - [horizontall] The scrollbar is oriented horizontally.
+//
+// ScrollbarHandle tags:
+//   - [vertical] The handle is oriented vertically.
+//   - [horizontall] The handle is oriented horizontally.
 type Scrollbar struct {
 	box        tomo.ContainerBox
 	handle     *sliderHandle
diff --git a/slider.go b/slider.go
index 0723b49..24e15ff 100644
--- a/slider.go
+++ b/slider.go
@@ -9,6 +9,17 @@ import "git.tebibyte.media/tomo/tomo/event"
 var _ tomo.Object = new(Slider)
 
 // Slider is a control that selects a numeric value between 0 and 1.
+//
+// Sub-components:
+//   - SliderHandle is the grabbable handle of the slider.
+//
+// Tags:
+//   - [vertical] The slider is oriented vertically.
+//   - [horizontall] The slider is oriented horizontally.
+//
+// SliderHandle tags:
+//   - [vertical] The handle is oriented vertically.
+//   - [horizontall] The handle is oriented horizontally.
 type Slider struct {
 	box        tomo.ContainerBox
 	handle     *sliderHandle
diff --git a/tabbedcontainer.go b/tabbedcontainer.go
index a8df8b9..7ff95e7 100644
--- a/tabbedcontainer.go
+++ b/tabbedcontainer.go
@@ -8,6 +8,19 @@ var _ tomo.Object = new(TabbedContainer)
 
 // TabbedContainer holds multiple objects, each in their own tab. The user can
 // click the tab bar at the top to choose which one is activated.
+//
+// Sub-components:
+//   - TabRow sits at the top of the container and contains a row of tabs.
+//   - TabSpacer sits at either end of the tab row, bookending the list of tabs.
+//   - Tab appears in the tab row for each tab in the container. The user can
+//     click on the tab to switch to it.
+//
+// TabSpacer tags:
+//   - [left] The spacer is on the left.
+//   - [right] The spacer is on the right.
+//
+// Tab tags:
+//   - [active] The tab is currently active and its contents are visible.
 type TabbedContainer struct {
 	box tomo.ContainerBox
 	
@@ -35,7 +48,7 @@ func NewTabbedContainer () *TabbedContainer {
 	tabbedContainer.leftSpacer.SetTag("left", true)
 	tabbedContainer.rightSpacer = tomo.NewBox()
 	tabbedContainer.rightSpacer.SetRole(tomo.R("objects", "TabSpacer"))
-	tabbedContainer.rightSpacer.SetTag("left", true)
+	tabbedContainer.rightSpacer.SetTag("left", true) // FIXME
 	
 	tabbedContainer.ClearTabs()
 	tabbedContainer.setTabRowLayout()