Conflicting handlers for org.eclipse.ui.edit.delete

[wutzebaer]

I get this error in my error log, and i cannot delete entries, seems there is an conflict with the multiproperties plugin (https://github.com/skazsi/multiproperties)

eclipse.buildId=4.9.0.I20180906-0745
java.version=1.8.0_144
java.vendor=Oracle Corporation
BootLoader constants: OS=win32, ARCH=x86_64, WS=win32, NL=de_DE
Framework arguments:  -product org.eclipse.epp.package.jee.product
Command-line arguments:  -os win32 -ws win32 -arch x86_64 -product org.eclipse.epp.package.jee.product

org.eclipse.ui
Error
Wed Mar 27 12:03:45 CET 2019
Conflicting handlers for org.eclipse.ui.edit.delete: {com.foosbar.mailsnag.commands.DeleteMessage@14422403} vs {hu.skzs.multiproperties.ui.command.DeleteHandler}