Hi Nick (@knolleary),
OMG... Have been debugging the whole palette editor to prepare a pull request. However it appeared that everything behaved alread correctly: my search string is already searched both in the node name AND in the node keywords. Thought I was getting nuts ...
For example, when I enter 'time' it displays my 'interval-length' node nicely (since it has a 'time' keyword):

Indeed when the palette editor is loaded the first time, both the node name and the keywords are all concatenated together into the 'index' property:
And when I have entered my 'time' search text, the editable list will be filtered based on the 'index' field:
The only thing I did wrong in my original post above, was that I had entered 'time' in the 'nodes' tabsheet instead of the 'install' tabsheet. Damn ...
So case closed.
If you are still on holiday, have a nice time on the beach !!!!
Bart

