• Date/time widget reset it's value to default after switch between Time Zones modes (Zone Names to Time Shift and back)
• Date/Time widget doesn't support seconds
• Date/Time widget Time zones names are not sorted by alphabet and it is very hard to find your zone there. I didn't found Prague there at all.
• Date/Time widget doesn't support search by name for Time Zone names

All mentioned issues can be fixed by merging two widgets with same functionality. See links below:
DMN version of Date/Time widget can be found here: https://github.com/kiegroup/kie-wb-common/tree/master/kie-wb-common-dmn/kie-wb-common-dmn-client/src/main/java/org/kie/workbench/common/dmn/client/editors/types/listview/constraint/common/typed
BPMN version of Date/Time widget can be found here: https://github.com/treblereel/kie-wb-common/tree/237190681b72db49e4cbbb189429260c2baea39b/kie-wb-common-stunner/kie-wb-common-stunner-sets/kie-wb-common-stunner-bpmn/kie-wb-common-stunner-bpmn-client/src/main/java/org/kie/workbench/common/stunner/bpmn/client/forms/widgets