Hi Evgeny,
Thanks for your feedback in this regard. This is a known issue in v3.3.0.0 and we do have open bug report - defect 858 on this. We will try our very best to address this issue at the earliest. You could track the progress of this bug fix at this link below :
Defect #858 - ContextTooltip should resize itself to fit its contents
We appreciate your patience and cooperation.
Regards,
Guru Patwal
Syncfusion, Inc.