Hi Witold,
Thanks for your interest in Syncfusion products.
You can customize Syncfusion BitmapTool to achieve your requirement.Since there is an issue in this,could you please create a DT incident for your query so that we can update with the patch?
You can create the DT incident from the following link.
http://www.syncfusion.com/account/dashboardIn the interests of maintaining confidentiality, we have a policy of not sharing patches or otherwise proprietary customer specific information in the public Forum.
Regards,
Pandi Murugan A