I'm too frequently, during "normal" operation (dev workspace with like many yangtools and controller projects open in it) seeing this exception make the Error Log pop-up, when probably this should somehow be "handled" (ignored?) in the code:

org.opendaylight.yangide.core.YangModelException: Does not exist
at org.opendaylight.yangide.core.model.YangElement.generateInfos(YangElement.java:216)
at org.opendaylight.yangide.core.model.YangElement.openAncestors(YangElement.java:247)
at org.opendaylight.yangide.core.model.YangElement.generateInfos(YangElement.java:207)
at org.opendaylight.yangide.core.model.YangElement.openAncestors(YangElement.java:247)
at org.opendaylight.yangide.core.model.YangElement.generateInfos(YangElement.java:207)
at org.opendaylight.yangide.core.model.YangElement.openWhenClosed(YangElement.java:276)
at org.opendaylight.yangide.core.model.YangElement.getElementInfo(YangElement.java:161)
at org.opendaylight.yangide.core.model.YangElement.getBuffer(YangElement.java:56)
at org.opendaylight.yangide.m2e.yang.YangBuildParticipant.validate(YangBuildParticipant.java:135)
at org.opendaylight.yangide.m2e.yang.YangBuildParticipant.access$0(YangBuildParticipant.java:130)
at org.opendaylight.yangide.m2e.yang.YangBuildParticipant$1.execute(YangBuildParticipant.java:120)
at org.opendaylight.yangide.core.indexing.JobManager.performConcurrentJob(JobManager.java:276)
at org.opendaylight.yangide.m2e.yang.YangBuildParticipant.build(YangBuildParticipant.java:117)
at org.eclipse.m2e.core.internal.builder.MavenBuilderImpl.build(MavenBuilderImpl.java:137)
at org.eclipse.m2e.core.internal.builder.MavenBuilder$1.method(MavenBuilder.java:172)
at org.eclipse.m2e.core.internal.builder.MavenBuilder$1.method(MavenBuilder.java:1)
at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod$1$1.call(MavenBuilder.java:115)
at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:176)
at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:112)
at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod$1.call(MavenBuilder.java:105)
at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:176)
at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:151)
at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:99)
at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod.execute(MavenBuilder.java:86)
at org.eclipse.m2e.core.internal.builder.MavenBuilder.build(MavenBuilder.java:200)
at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:735)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:206)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:246)
at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:301)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:304)
at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:360)
at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:383)
at org.eclipse.core.internal.resources.Workspace.buildInternal(Workspace.java:487)
at org.eclipse.core.internal.resources.Workspace.build(Workspace.java:399)
at org.eclipse.oomph.setup.internal.core.SetupTaskPerformer$3.run(SetupTaskPerformer.java:3066)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55)