Open DP client > View > Uncheck Detail View, Forecast Comment, Querry.

Open Forecast graph and maximize its size.

Then close the DP client a log again. Open forecast graph. It will show without any issue.
Close the DP client again and log again. Client will not open as it is crashed.

This has been fixed in APP10 UPD 4 onwards.

For any issues reported below UPD4, below workaround can be used. 

Go to regedit, HKEY _CURRENT_USER>SOFTWARE>IFS>Demand Client and delete that.
Open the Demand Planner client again with settings again. Then DP client will be open without any issue once the registries are deleted.