In a web graphic hosted on a Xenta Server, clicking to change a value displays the dialog momentarily, then it immediately disappears.
The Java version is too new or too old.
Make sure The java versions installed have been tested against the installed Xenta version.
A Compatibility Matrix can be found on The Exchange Download Center. Or see Software and Firmware compatibility matrix for older versions of the traditional product lines.
If the wrong versions are installed, download the correct version and install it.