Ghost touch means the device appears to receive touches you did not intend. It can look like typing by itself, random taps or a marker jumping away from your finger. A dead area is different: an intended touch does not arrive. Write down which behavior occurs before changing settings or replacing parts.
Make the first observation with your hands clear
Open the multi-touch canvas and place the phone on a dry, stable surface. Keep fingers, sleeves and the edge of your palm away from the screen. Watch for markers without intended contact. Then place one fingertip and move slowly inside the canvas.
A marker is evidence that the browser received a touch event, not that it found a defective digitizer. Accidental edge contact, moisture, OS behavior or a hardware problem can produce unexpected events. Also remember that browser edge gestures can cancel an intended contact and make a marker disappear.
Change one condition at a time
- Dry the surface and hands. Gently clean according to the phone's instructions. Retest without pressing harder. If the phone has been exposed to liquid, follow its drying guidance before charging or extended testing.
- Disconnect the charger. Compare the same gesture on battery power. If the symptom occurs only with a particular charger or cable, stop using a suspect accessory and compare a known-compatible one after the device is dry.
- Check the case and protector. Inspect lifted edges, trapped debris or pressure from a case. Remove an easily removable case for comparison. Avoid peeling a damaged protector or dismantling a phone when doing so could worsen damage.
- Compare apps. Repeat a slow gesture in another browser or a native drawing app. If the symptom belongs only to one app, investigate that app before concluding the screen is physically faulty.
- Restart and repeat the same sequence. Note whether the change persists, rather than assuming that a brief improvement identifies the cause.
This comparison is especially useful when the problem is intermittent. Record the exact condition—“three extra touches while connected to this charger”—instead of “screen sometimes bad.” A single clean run does not exclude a recurring fault.
Map a suspected dead area
Use the 96-region coverage grid. Reset it, then draw slowly across each row with one finger. If a region remains empty, approach it from more than one direction. Rotate the phone and test the same physical area of glass, allowing for the page's changed layout.
An empty region can be untested. Browser event sampling can miss a fast stroke, and the page does not receive input behind browser chrome or its own controls. Repeated failure at the same physical location in several apps is more informative than one incomplete grid.
When only several fingers cause trouble
Return to the multi-touch canvas. Hold two separated fingertips down, then add a third without lifting the first two. Watch the active count and IDs, then lift one at a time. The session maximum records what was actually observed; it does not discover the panel's absolute supported maximum.
If a contact vanishes when fingers are close together or near an edge, repeat with more separation. Palm rejection and system gesture rules can affect the result. A laptop trackpad usually does not expose individual fingertip contacts to this tool, so it is not a substitute for testing the phone touchscreen itself.
Preserve evidence without treating the tool as repair
Save the session counts and your assessment. If the fault is intermittent, a short recording made with another camera can show your fingers and the unwanted response together. Avoid recording messages, passwords or other private content while documenting it.
Browser tests cannot recalibrate a digitizer, repair a flex cable or determine whether a replacement screen is genuine. Persistent unexpected touches after basic comparisons, cracks, a lifting display or trouble that started after impact merits professional inspection. If the visible picture itself has dots or patches, use the display inspection separately; a touch issue and a display defect can coexist.