line annotation does not work with y-axis set to my own custom axis

Hi objo,
I create a custom axis (derived from Axis), and overrides below methods:
1) GetTickValues
2) IsValidValue
3) IsXyAxis
4) Transform

the custom axis appear to work well on the plot as axis Y (this axis has pan and zoom disabled always). However I later found out that when I add vertical line annotation, it will not show in the plot. Horizontal line annotation works well on the other hand.

Is there anything that is depending on axis-Y (my custom axis) when I add vertical line annotation?

I have found the reason why the line annotation wasnt rendered however the fix is still something that I will research further later as I need to move on to other thing now. Will post the code changes and some suggestion later. Thanks objo.