The only way to get color from a library item is to sample it. The default color for stroke is white, the default for fill is red solid. When you have a shape tool selected the stroke and fill are available there so you can click in the tool bar to bring up the color picker and then sample from there. If you have any color except the default red for fill or white for stroke you can press the U key twice quickly to bring up modified properties for the shape and have direct access to the color sample tool from the time line. That's my usual practice. In fact, almost every time I create any shape I'll press the u key twice immodestly to access the modified properties of the layer so I can see everything modified and make fine tune adjustments.
Hope this helps.
Thanks, but thats not really fast.
After Effects should be more like Photoshop,
doubleklick on the color from the library and the shape or type changes its color.
The library is not usefull in AE at all and its not possible to put new colors into it,
for collaborating with other people or using in other projects.
or do have any idea how to use the library properly within AE ?
Could be better but that's the way color has always worked in AE and the way it worked in Photoshop for many years. File a feature request...