This bug was originally marked as duplicate of bug 213434, that is already resolved. This bug is still valid, so this seems to be another bug, but it might be related.

Build: NetBeans IDE Dev (Build nbms-and-javadoc-9325-on-20120622)
VM: Java HotSpot(TM) Client VM, 23.1-b03, Java(TM) SE Runtime Environment, 1.7.0_05-b05
OS: Windows 7

User Comments:
mcneill.cc: Saving an edit to jsp file.

GUEST: Editing an html page

GUEST: Unknown cause. Typing, I don't think a context menu was trying to come up. I just randomly got an alert with no slowdown.

kolen: Pressed autocomplete in html file editor

kolen: Pressed ctrl+shift+space (show method documentation) in php file editor.

mcneill.cc: Saving a JSP page.

jyeary: Code completion.

kolen: Put cursor to variable inside expression in PHP file and pressed ctrl+shift+space (show documentation).

kolen: Put cursor on variable in php file and pressed ctrl+shift+space (show documentation).

yyq2008: Let IDE tip jsf managedbean name on jsf page.

mcneill.cc: CTRL + S save js file.

schkovich: back space during code completion wondering about class constants defined




Stacktrace: 
java.lang.NullPointerException
   at org.netbeans.modules.html.editor.completion.HtmlCompletionProvider$DocQuery.doQuery(HtmlCompletionProvider.java:232)
   at org.netbeans.modules.html.editor.completion.HtmlCompletionProvider$AbstractQuery.query(HtmlCompletionProvider.java:281)
   at org.netbeans.spi.editor.completion.support.AsyncCompletionTask.run(AsyncCompletionTask.java:223)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1452)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2032)