fix see https://github.com/sagemathinc/smc/issues/918 -- "jupyter: be more careful when checking for unsaved changes when load not quite done yet"
fix see https://github.com/sagemathinc/smc/issues/918 -- "jupyter: be more careful when checking for unsaved changes when load not quite done yet"

tscholl2/smc,sagemathinc/smc,tscholl2/smc,tscholl2/smc,sagemathinc/smc,DrXyzzy/smc,DrXyzzy/smc,sagemathinc/smc,tscholl2/smc,sagemathinc/smc,DrXyzzy/smc,tscholl2/smc,DrXyzzy/smc