Hi, all!
Miracles continue - IMC v7.2 E0403P10 did not work properly: every time after IMC-host was rebooted, within few hours fully stopped coming events from the monitored equipment (counters in status bar in low left corner are "frozen", no any e-mail alarms on critical alarms etc). And stopped to work widget 'Important Devices' - it became empty.
In /opt/iMC/client/log/imcforeground.log file I found an error:
java.lang.OutOfMemoryError: GC overhead limit exceeded
In accordance with the recommendations from the document "H3C IMC Platform Troubleshooting Guide" I have increased Max Heap memory size first from current 2048 to 3072 then from 3072 to 3584 (further increase can't be - no more available RAM) but it did not help: about two o'clock in the morning, this error appeared again in the log.
As a result, I had to revert back to the version E0403P06 - and these problems have disappeared. But came back the problem with non-working link "Modify Display Indexes" (java exeption).