A Setter's Tragedy by Wan

The tragedy for Wan was that the grid just wouldn’t work; some entries clash and two others are too long for their entries. At that stage, Wan realised that a device was in the grid that would enable solvers to raise and lower elements in order to resolve the clashes, though it does still leave four non-words in the grid. Solvers must highlight the device (12 cells) which at any stage would be considered somewhat contrived and inartistic. To help solvers detect the device, Wan has left out a thematic word from six clues, two of which lead to entries that are crucial to the dénouement. Entry lengths are shown. The Chambers Dictionary 13th edition is recommended.

    1    Rumour going round by letter about bad nuts and fruit (12, 2 words)
    9    Wall of sound finale (7)
    11    Leg stocking rector found by edge of Bermuda grass (5)
    12    Most of money goes west to make cloth (4)
    13    Gross sound when Henry moves (6)
    15    A translator in translating a Greek letter’s taken aback to find an element in Latin (7)
    18    Plane leaves its last country (5)
    19    Fire door, perhaps, contains college fire ultimately (6)
    20    Downgrade French word found in abridged document (6)
    23    Travels to Ed’s place in France (6)
    25    One local transfixed by strange noise almost makes a sound of the same pitch (6)
    27    Sneak, retired, ready in Afghanistan to hide gold in retirement (5)
    32    Worried pilot scratching fighter plane in workshop (7)
    34    University in Egypt or what was Egypt c1600 (6)
    35    Stable government ignored by sudden movement of the masses (4)
    36    Instrument to finger one’s back (5)
    37    Weed keeps old informer prisoner (7)
    38    Woodworking degree dons deem dull, so rule out (12, 2 words)
    2     Partridge, maybe, heading up a ravine (4)
    3     Quickly on rising getting sexy (6)

4     Take recording company, finished, unknown type of recording (5)
5     Accumulation of fluid made European ill (5)
6     Maybe Pat’s emotional cry when Juliet drops from tree (5)
7     Party members mostly support uprising (4)
8     Weasel from Scots town recruited by army (5)
9      Pressure on prodigy who hasn’t won is deliberate (6)
10    Signs in music do seem funny occasionally (6)
11    Butcher’s short of good blade (5)
14    Wait darling to engage, no good pursuing my heart?  (6, 2 words)
16    Check pressure inside bottles (4)
17    Brewed Earl Grey to drink without a measure in work (6)
20    Earned too much turning up for performance (6)
21    Rob used to make powder (4)
22    Knocked off out of book, a bird dish (6)
24    Bore always takes time to cover second base (5)
26    Screw in prison having lost leg, managed on one left (6)
27    Pretend to drop from flattening (5)
28    Cavalryman once mounted taking part in National Hunt (5)
29    Shorten long stick which might make a candlestick (5)
30    Think to free university of plaster (5)
31    It's necessary heading north, but not very necessary in Eastern Europe (4)
33    Terminal in France masks height of jumbo well! (4)
To enter this competition, send your entry as an image or in list format giving the highlighted device to ccpuzzles@talktalk.net before 8th December 2017. The first correct entry drawn from the hat will receive a book donated by  Chambers.