- Success Criterion 1.4.10
- Conformance level AA
Modal Dialog Wider Than the Viewport With Unreachable Buttons
1.4.10 — Reflow
Scenario
Setting
A weather app's forecast screen
What’s wrong
Modals wider than viewport with internal 2D scrolling and unreachable buttons.
Example
On a weather app's forecast screen: modals wider than viewport with internal 2D scrolling and unreachable buttons.
Why it matters
Low-vision users at high zoom and people reading on narrow mobile viewports. The practical effect on a weather app's forecast screen: they can't perceive the control's boundary or state.
How to test
Set the viewport to 320px and open modals: if a modal is wider than the viewport and requires internal 2D scrolling to reach its buttons, it fails.
How to fix
At 320 CSS px width (400% zoom on a 1280px desktop), content must reflow into one column with only vertical scrolling and nothing missing or unreachable.
Outcome
That one change on a weather app's forecast screen means they read the text clearly against its background.
Who is affected
Low-vision users at high zoom and people reading on narrow mobile viewports.
Learn more
- Understanding Understanding document (opens in a new tab)
Related scenarios
- Content or Controls That Vanish Entirely When the Page Reflows
- Vertical Content That Forces Horizontal Scrolling at 320px
- Fixed-Width Container Forcing Scrolling in Two Directions
- Overlapping Content When the Page Is Zoomed to 400%
- Sticky Bars That Eat Up Most of a 320px Mobile Screen
- Desktop Breakpoint That Never Switches to Mobile Layout