T540p mouse click bug!

mysterious hardware

Posted by design0er on August 11, 2018
More Code, More Bug.

0x00 The thing

Lenovo T540p laptop produced by 2015,

Windows 7 SP1 64bit used for 3 years, good habit of OS protecting.

Lots of software, but don't have any harmful things on it.

0x01 The bug

Level 1

A few times of mouse click error, left click turns into right click, the context

shows on the application window when I just use left click.

Sometimes, both the left and right not working, the application like Chrome / File Explorer don't respond

for mouse click.But the keyboard works normally.

This due to the Bluetooth mouse battery low, just replace a new battery will solve.


Windows have an internal function to switch left click and right click, this bug have nothing to do with that one.

  • The switch function change mouse click mapping permanent, after switch setting, every left click is mapped into "context menu command", every right click is mapped into "just left click here";

  • The bug show randomly, which cause left click turn the context menu for almost 5 minutes, or the left click on application window don't work, the background window will not respond when you click on it, just sucks!

Level 2

  • the bug continues, though you add on the new battery.
  • then you should update the latest touchpad driver, restart system.
  • the bug will gone.

Level 3

  • the updated driver haven't fix the bug.

  • after update driver and restart, switch into the windows safe mode,

    here, do some click, the bug won't show. Check if your trackpoint or touchpad or wireless mouse would cause the phenomenon.

    1. If the mouse does, then replace a new wired mouse (don't use a wireless one). Check if this is useful.
    2. If the trackpad and/or touchpad cause the problem, then in the control panel, mouse -> only use trackpad or only use touchpad. Check if these 2 things cause the bug. Then you may lost one of them, use the mouse instead.
    3. sometimes, reset setting to default may works.

Level 4

  • nothing works!
  • sometimes, it may work in safe mode, but it comes again in normal mode after reboot in few seconds.
  • the bug continue, if you disable one of three devices: the mouse / the touchpad / the trackpoint.

Level 5

  • abandon the trackpoint & trackpad. use the keyboard & mouse like PC.
  • reboot into BIOS, by press F1 on boot logo.
  • the bug disappears with the functional trackpoint & the trackpad. config -> keyboard & mouse -> disable trackpad & touchpad.

The Origin

  • hardware broken, or something like the component current cause the chaos.
  • system driver bug. low level programmer!
  • system/user level application/driver conflicts. you may have noticed that the bug won't show in the safe mode, even no config is changed. But that's just tell me that: your 300+ application/driver cause the bug, the hardwar may be innocence! Then i can do nothing.
  • if other model of thinkpad laptop show these bugs, then lenovo or windows would take the accusation.
  • the original keyboard may be innocence. it always works.

The Solution

  • Check the mouse battery, change a new one.
  • Use a wired mouse instead of a Bluetooth one.
  • Check the settings of trackpoint/touchpad.
  • Check the firmware update for your model and OS type.
  • Disable one of the 3 things. Check if this help.
  • Final steps: disable touchpad & trackpoint in BIOS. abandon the classic thinkpad redpoint and touchpad.