Since last versions of Siebel don't allow logging in through GET requests (credentials in URL address), it is now a bit more challenging to have a "log into Siebel" browser bookmarks. However, we can acheive the same by sending a POST request. Check it out in the below example.
Quick description:
A single-file page to orginise all Siebel links which allow you to log into Siebel thin client in one click.

Setup instruction:
- Download a Sample page (right click - Save link as ... / Save target as ...).
- Open the page in text editor, and update it with your structure and credentials following inline comment tips:
- each level of grid can have url, usr, pwd attributes defined
- url is concatinated from top to bottom
- usr and pwd give a priority to the deepest level
- usr = '*' when you want to specify credentials manually
- Open the page in browser and make it your home page.