Count the fingers you hold down, not the taps you make
Five separate taps are five events but only one simultaneous contact. To test five contacts, keep the first four down while placing the fifth. Lift them one by one and check that the active count falls accordingly. Browser-assigned IDs remain stable while a contact is tracked; a new touch can get a new ID.
The session maximum is the most contacts seen at once. It is a lower bound on what this session demonstrated, not your panel's certified limit. A run with one contact does not prove that your screen only supports one.
Look for three different symptoms
- A dead area: a marker repeatedly stops or disappears in the same region while your finger stays on the canvas. Check that region with the touch coverage grid and rotate the device to compare the same physical area.
- Ghost touches: markers appear where you did not place a finger. Dry the screen, disconnect the charger and repeat with your hands clear of the edges. The ghost-touch guide gives a controlled comparison.
- Inconsistent multi-touch: individual fingers work but a contact disappears when another is added. Repeat with well-separated fingertips, then compare another app. OS gestures, palm rejection and browser cancellations can resemble hardware faults.
Mobile testing boundaries
The testing canvas fills the available dialog space below its controls. It cannot test behind browser chrome or the control strips. Touches outside it are excluded. Avoid navigation gestures at the edges; do not press harder on an unresponsive screen. A mouse or pen is deliberately excluded from the touch count. Laptop trackpad gestures usually become scrolling or pointer events rather than raw touch contacts.
Markers and contact paths stay on this page. The saved summary contains session counts and your observation. To distinguish visible display damage from input failure, use the visual dead-pixel test.