Thanks for your bug report.
1. The rich text editor does not show on Google Chrome on Linux when creating a new post, but it appears when the post is edited - I think i noticed this some times. That's a bug more related to the TinyMCE integration into Moodle 2, which was heavily worked on. And Petr plans to do more work on it.
2. Yep, icon is now fixed.
3. The bug that shadows do not render in Google Chrome is known. The problem does not affect Safari, even if it uses the same rendering engine. Here's the upstream bug report:
(maybe you can place a vote for the bug, by starring the issue, hehe)
4. Regarding the undo issue, please try to reproduce the bug and provide the exact steps. This is too vague and I don't know what could have went wrong.
5. Regarding the border width and the font size errors .... please tell me more details. Are you using Google Chrome on Linux? Which version and build? It should be noted Google Chrome is quite ... alpha/unstable. At times the ellipse tool failed to work in Chrome on Linux, then it got fixed, and etc. The browser is not a very good measure for PaintWeb due to their bugs.
Please retest in a different browser and let me know if those work or not - reproducible steps are best. These work for me.
6. The fill tool? You can have text drawn with a fill, see the Border tab, shape type: filled, strokes only, or both. The bucket tool is missing at the moment and it's planned.
7. Text cannot be split across multiple lines, at least not now.
8. By pressing Escape while the Text tool is active you go back to the previous drawing tool. Suggestions for a better user interaction are welcome.
If you want, you can use the PaintWeb issue tracker at Google Code, so we do not clutter this place. If you decide to do so, please post only one issue report for each problem you encounter. If that is too much trouble, then please reply here.
Thank you very much again!