Adjusting automation volume by 1dB in PT 10

[cristol2k]

New to Pro Tools, I am not finding a solution to this in Pro Tools Help, the knowledge base or the DUC forums: When mixing, when I have selected the entire graphical automation volume line for one track, for the length of the song, and want to lower or raise the volume of the entire track (all breakpoints) by 1dB, the line will only move in 2dB increments no matter how slightly I move the mouse with the Trim tool. Alternatively, when I try to use the pop-up Vol fader on that track in the I/O panel, the value changes there but it doesn't seem to affect the automation gain. There must be some way to achieve a 1dB volume change? Seems like this would have been in the documentation; sorry if I missed it.
Many thanks.

PT 10.0.1
OS X 10.6.8