IE 9 accelator freezes UI in modal popup


We are using Vaadin 7.1.7 and UI is running in IBM Websphere Application Server 8.5.

Application has many modal popup windows.
In every modal popup with IE 9 if user selects some text an accelerator button is shown.
If user touches that button the UI is frozen.

Is there any way to get rid of this behaviour?

Our client is not willing to configure all PC’s and IE browser to disable the accelerator.
And they are not upgrading to IE 10.

Have found this
but I am not able to get the HTC file working in IE 9.