Progress API question

Hi,
If I'm use cancellable progress window from time to time on cancel users get something like

Error message: SelectViewTable
com.intellij.openapi.progress.ProcessCanceledException
at com.intellij.openapi.progress.util.c.checkCanceled(c.java:58)
at com.intellij.openapi.progress.a.a$0.run(a$0.java)
at com.intellij.util.g.d.a(d.java:68)
at com.intellij.openapi.progress.a.a.checkCanceled(a.java:11)
at com.intellij.psi.f.f.bw.a(bw.java:5)
at com.intellij.psi.f.f.n.f(n.java:8)
at com.intellij.psi.f.f.n.getText(n.java:2)
at
com.propertiesEditor.propedit.action.PropertiesFindUnusedPropertiesFromBundl
eAction.findUnusedProperties(PropertiesFindUnusedPropertiesFromBundleAction.
java:237)
at
com.propertiesEditor.propedit.action.PropertiesFindUnusedPropertiesFromBundl
eAction.access$300(PropertiesFindUnusedPropertiesFromBundleAction.java:59)
at
com.propertiesEditor.propedit.action.PropertiesFindUnusedPropertiesFromBundl
eAction$5.run(PropertiesFindUnusedPropertiesFromBundleAction.java:178)
at com.intellij.openapi.progress.a.a.runProcess(a.java:0)
at com.intellij.openapi.f.b.c$1a_.run(c$1a_.java:3)

How to fix this issue? May it problem of wrong using API?

TIA,
Dmitry