Incompatibility with Oracle JRE 1.8_281 : GUI freeze

Hello everybody,

We are using docking frames for a while without any trouble.
But, since Oracle JRE 1.8_281 (and 291) something went wrong in focus manager (that my understand of the problem).
When file drag and drop is performed, the dockable application is freeze.
Stack exploration does not show somehting wrong : no thread blocked.
If a DefaultFocusRequest is trigger with a null component, very often, the Java application freeze.
I have spent severals days to resolve the problem without solution.
Can somebody could help me solving this trouble ?
Thanks for your help,

Looks like a new bug to me. I’ll have to investigate too (I won’t promise a fast solution)

What OS are you using?

Does your app do anything fancy that could be related to this issue? Does the app do anything with „focus“?

Hello Beni,
OS is Windows 7 64bits
I have produced a very small sample for testing bug producing. How can I give you the code to help ?
My sample is composed of two DefaultSingleCDockable.
When file is drag over the frame, event is catch by the frame in order to set toFront one DefaultSingleCDockable.
Quite simple, nothing special done on focus.

You can attach a ZIP file here to your messages :slight_smile:

Or if that does not work: send it directly to

I’m not authorized to attach a zip as i’m a new user…
I try by mail.



I’ve got your mail. Could not reproduce the issue on my Linux - I’ll try out a windows system later.

I hope you will reproduce it under Windows :upside_down_face:.
Thank you so much

I tried to reproduce the issue on Windows 10, x64, with JDK 1.8_281.

I did drag a file over the tabs, and the Dockable associated with the tab got focused. I could move the file around, but I never experienced any freeze.

You wrote:

OS is Windows 7 64bits

… that is a system I can not test. My last computer with a working copy of Windows 7 died last year. At this point I can only suggest to either downgrade your JDK to pre 281, or upgrade your OS.

hello Beni,
My collegue try under Windows 10, he reproduced also the issue.
He tell that it takes „a little time“… You need to go in/out dragging file on panel, button, out of frame to get and lost the focus, relativly fast…

I send you by mail a screen shot to show you dockable configuration to produce the issue.

I Beni,
I have also post a question on StackOverflow java - Oracle JRE 1.8_281 GUI freeze - Stack Overflow.
The workaround does not work on my sample using DockingFrames.
I’m pretty sure that the bug is inside JRE 281.
I’m not sure that disable drag event on dockable will be successful enought has the trouble seems to be on Windows desactivation and focus lost…