"The Dance" painter (7)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">the dance painter</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for matisse that I've seen before include "French painter, d. 1954" , "French painter, Henri, d.1954" , "20th century French painter" , "Henri --, French artist" , "Leading fauvist painter, d. 1954" .)