Hi Gilbert --
I believe the way that Visio does isometric lines is the issue here. The
isometric "feature" is more or less an "extension" from an existing shape.
So, if you try to draw a random line at 30 deg, you will only see the 45deg
guide.
It gets a little worse. Seems that this "feature" only works well with
shapes, like squares & rectangles. If there is a a simple horizontal or
vertical line, you may or may not get the isometric angle guides. "Flaky" at
best is how I might describe the behavior of the isometric line feature.
Wapperdude