Java Security FAQ: Create a window from an applet
Here's an applet that creates its own popup window. You should notice
that the popup window has a yellow warning banner when it's run from
appletviewer, and it is labeled with the "broken key" icon when it's
run from Netscape Navigator 2.0.
Here's the source.
Conclusion:
Any windows created by applets will be labeled with a warning. Sorry,
you can't prevent this! We know that UI experts cringe, but we want
applet windows to be clearly identified as applet windows.
Back to the Java Security FAQ