Only hide bufferlist when switching to mobile

Showing the keyboard on mobile will trigger a resize event, therefore
trying to use the bufferlist filter will actually hide the bufferlist
making the feature unusable. Bug introduced by 554b1669.
Rename isMobileDevice to isMobileUi

Right now we are only checking the width screen so we are not
detecting anything that is mobile specific. Will rename to
isMobileDevice when we introduce more specific checks.