See issue #246161.
Fixed jet-main 9290556b5426.
When the previous request finished and the next entered text is narrowing of the previous text the content of Go To Symbol dialog is filtered rather than performing the query.
Integrated into 'main-silver', will be available in build *201504030001* on http://bits.netbeans.org/dev/nightly/ (upload may still be in progress)
User: Tomas Zezula <firstname.lastname@example.org>
Log: #251535:Go To Symbol is refreshing the whole list.