Just email me - cannon@inmed.univ-mrs.fr. Be sure to mention the version you are using, and if reporting a bug send a model showing the problem if possible.
It is well worth reading the graphs section in the user interface documentation. The behavior is predictable, if complicated.
However, you can also do most things from the keyboard. Move the mouse over a graph and press the "h" key ( or select the "help" option from the menu in the top right of each graph). This give you text fields to type numbers in to set the ranges.
Put the mouse over the slider and press return. Type the number you want at the keyboard and click "ok".