In the current 6.0 build (rc) all the common Java dialogs, except file, print and page dialogs, follow the rule: the dialog is shown in the windows taskbar only if it is parentless. The situation with file, print and page dialogs is a bit different.
File dialogs are shown in the taskbar regardless of their parents. This is what AWT bug 6488834 is about. After the fix for 6488834 all the file dialogs will follow the same rule as all the rest dialogs, i. e. the will not be shown in the taskbar if their parent is not null.
Print and Page dialogs (bot native and Java) are always shown in the taskbar too, but the fix for 6488834 can't fix this problem as the problem lies in Java2D code, not in AWT. After the fix for 6302514 print and page dialogs are always created with a null parent, which is not completely right. I beleive if a parent is specified for a print dialog (this cannot be appliet to page dialogs) then it shouldn't be visible in the taskbar. At the same time the fix for 6402514 must not be broken: if a print dialog is created with a null parent and some toolkit-modal dialog is visible, then the print dialog should be blocked. However, if this toolkit-modal dialog is passed as a parent for a print dialog, then the print dialog should remain alive and block the toolkit-modal dialog.
Also, it would be fine to have an API to provide a parent for Page dialogs like it is possible for Print dialogs with getPrintJob method in java.awt.Toolkit class. This parent then can be used to determine if the page dialog should appear in the taskbar or not.