If your data contains text with non-Latin characters, e.g. Asian language characters, you must make sure that the fonts you use for the editor and the grids in DbVisualizer support those characters.
Open Tools->Tool Properties, select General / Appearance / Fonts, and change the selection for the Grid and/or the Text Editor to an appropriate font. You can use a sample string of your choice in the desired character set and preview the rendering in each font by stepping through them in the dialog.
Since DbVisualizer uses the fonts installed in your operating system, you may need to search the net and install a suitable font if none of the installed fonts renders your characters properly.
Note: Even if the font can render the characters, data may still be scrambled in DbVisualizer. The most common reason is that the encoding between the JDBC driver and the database is wrong. Please check the JDBC driver documentation for a driver property to set an alternative encoding.
The available fonts and supported character sets vary with the operating system version, but the standard Java fonts Dialog (proportional) and Dialog Input (monospaced) work in many cases.
For Microsoft Windows, the Microsoft SimSun (monospaced) and YaHei font families support several non-Latin character sets (e.g. Simplified Chinese, Japanese, Greek, and Cyrillic). In addition, Microsoft New Tai Lue can be used for Thai.
Please refer to the documentation of your operating system for a full list of fonts and supported character sets, e.g. the Windows 11 font list.
For the benefit of other users, please let us know if you can recommend fonts for languages not covered here!