Without knowing many more details, the best guess we can offer is to install the latest patch and hope it includes a fix for the problem. Also, if you are using any Java version newer than 1.5, this may be the cause of the problem. Java 7 or newer is not supported at all with Forms 10. And Java 6 is only supported on patched versions of Forms 10. This may be the cause of the problem too. Refer to the iAS 10 Certification page for details:
I encourage you to consider patching your environment for reasons other than just the current one. I further encourage you to use a currently supported version like 184.108.40.206. If you do not have current license and/or Support contract, I recommend you contact Oracle Sales.
Dear Michael Ferrante,
thanks for your quick reply. I appreciate your solution. It is the final solution that we upgrade our application server and developer suite to patch 3. But currently I am unable to get patch set 3.
some where I had read that there is a jar file. If we place that jar file in java folder than combo box perform normally. I have lost the link of this solution.
This jar file could only be the frmall.jar as it would contain any component of the Forms Applet. Replacing the (original) frmall.jar with a custom built one is a dirty hack at best, and might get you in troubles in some completely different place. If you get this jar file from somewhere else I wouldn't trust it either as it has to contain a fix by Oracle which must be obtained via Oracle Support. So whoever is giving you this jar file for free is breaching his support contract at best or injecting some bad code into your System at worst. In any case I wouldn't trust them.
So the only real solution would be to patch your system to the latest patchset, or upgrade to the latest version (220.127.116.11) as Forms 10 isn't even supported anymore.
There is a known bug with the ComboBox item in Oracle Forms 10g R2 (10.1.2.0.2). This was fixed with Patchset 3 (which requires an Oracle Support Contract to download the patch) which is why Micheal is recommending you install this patchset. If you don't have a support contract - your options are: 1) Don't use the ComboBox item. 2) upgrade to latest available version of Oracle Forms on the Oracle Technology Network (OTN) which is Oracle Fusion Middleware 11g R2 (18.104.22.168.0). 3) Lastly, continue using the Oracle Jinitiator.