Fix error when using Generic Search Widget

It seems like the "Generic Search" widget does not work anymore: upon clicking the save button, I always and with an "An error occured!" message, here is the related stacktrace.

Thanks

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Uncaught exception: com.google.gwt.event.shared.UmbrellaException: One or more exceptions caught, see full set in UmbrellaException#getCauses
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
Caused by: com.google.gwt.core.client.JavaScriptException: (TypeError): a is null
fileName: https://connect.nuxeo.com/nuxeo/site/studio/ide/studio/CF9E0B7FC19BBE21C2F0479D8B815281.cache.html
stack: CCd@https://connect.nuxeo.com/nuxeo/site/studio/ide/studio/CF9E0B7FC19BBE21C2F0479D8B815281.cache.html:4757
Shd@https://connect.nuxeo.com/nuxeo/site/studio/ide/studio/CF9E0B7FC19BBE21C2F0479D8B815281.cache.html:8173
Eqd@https://connect.nuxeo.com/nuxeo/site/studio/ide/studio/CF9E0B7FC19BBE21C2F0479D8B815281.cache.html:8250
Bhd@https://connect.nuxeo.com/nuxeo/site/studio/ide/studio/CF9E0B7FC19BBE21C2F0479D8B815281.cache.html:7028
cid@https://connect.nuxeo.com/nuxeo/site/studio/ide/studio/CF9E0B7FC19BBE21C2F0479D8B815281.cache.html:8247
zv@https://connect.nuxeo.com/nuxeo/site/studio/ide/studio/CF9E0B7FC19BBE21C2F0479D8B815281.cache.html:8220
jz@https://connect.nuxeo.com/nuxeo/site/studio/ide/studio/CF9E0B7FC19BBE21C2F0479D8B815281.cache.html:7862
Yy@https://connect.nuxeo.com/nuxeo/site/studio/ide/studio/CF9E0B7FC19BBE21C2F0479D8B815281.cache.html:7366
rxb@https://connect.nuxeo.com/nuxeo/site/studio/ide/studio/CF9E0B7FC19BBE21C2F0479D8B815281.cache.html:4258
Zu@https://connect.nuxeo.com/nuxeo/site/studio/ide/studio/CF9E0B7FC19BBE21C2F0479D8B815281.cache.html:7004
txb@https://connect.nuxeo.com/nuxeo/site/studio/ide/studio/CF9E0B7FC19BBE21C2F0479D8B815281.cache.html:6714
Fxb@https://connect.nuxeo.com/nuxeo/site/studio/ide/studio/CF9E0B7FC19BBE21C2F0479D8B815281.cache.html:8223
Xmb@https://connect.nuxeo.com/nuxeo/site/studio/ide/studio/CF9E0B7FC19BBE21C2F0479D8B815281.cache.html:6375
Gob<@https://connect.nuxeo.com/nuxeo/site/studio/ide/studio/CF9E0B7FC19BBE21C2F0479D8B815281.cache.html:8179
Zj@https://connect.nuxeo.com/nuxeo/site/studio/ide/studio/CF9E0B7FC19BBE21C2F0479D8B815281.cache.html:4828
ak@https://connect.nuxeo.com/nuxeo/site/studio/ide/studio/CF9E0B7FC19BBE21C2F0479D8B815281.cache.html:7512
@https://connect.nuxeo.com/nuxeo/site/studio/ide/studio/CF9E0B7FC19BBE21C2F0479D8B815281.cache.html:6237

lineNumber: 4757
columnNumber: 18
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)
at Unknown.anonymous(Unknown Source)