I do not understand why whenever I go to select the rectangle/polygon(or other similar tools) sometimes-in the options bar-the path functions(subtract from area, add to shape area etc) are NOT available.
The one who is always available is the "create new shape layer".
What might be the cause of the above problem?
This can happen when no layer is selected, e.g. when pressing with move tool on any pixel on the background layer. It is observed on all photoshops, CS2 for example.
What version of photoshop?
Generally those options are grayed out if you don't have a shape layer already active.
I found the solution. I must be carefull not only to have the layer selected but also its mask.
When the mask is unselected the path features are NOT available.