Hm..You will probably have to wait for our dev Manfred to answer you this question. He is on a holiday this month so he will not be online that often, but he will answer eventually.
You can always make a backup of your data directory including your wallet file before you try anything, so you don't lose any bitcoins you might have deposited in to the Bisq wallet.
You can always try to restart your Bisq client and even your PC, if it doesn't work, and see if somehow it gets fixed.
And if you don't have any open trades at the moment you could even try to reinstall your Bisq client, you could also withdraw your bitcoins to an external wallet before doing so, if you feel more secure. Backup of Bisq data folder should be enough tho.
You can find the data folder at:
- Mac OSX: /Users/username/Library/Application Support/Bisq
- Linux: /home/username/.local/share/Bisq
- Windows 7,8: C:\Documents and Settings\username\AppData\Roaming\Bisq
- Windows XP: C:\Documents and Settings\username\Application Data\Bisq