A user reported to me that they are unable to create a PSBT with a legacy watchonly wallet when they use the GUI. They get an error "The amount exceeds your balance".

I think the issue is that the GUI will retrieve the wallet's balance via `AvailableCoins` before calling `CreateTransaction`. This call to `AvailableCoins` is resulting in fewer coins being returned with recent changes to how `AvailableCoins` works, particularly with additional filtering of spendable coins and preset coins.

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Note that this does not effect descriptor wallets. A workaround for this issue is to switch to using descriptor wallets. An existing legacy wallet can be turned into a descriptor wallet using the `migratewallet` RPC. However many watchonly legacy wallets are likely the result of importing descriptors via `importmulti`. For such wallets, I recommend creating a new descriptor wallet and re-importing the descriptors.
{
    CMutableTransaction tx;
    TxState state = TxStateInactive{};
    tx.nLockTime = lockTime;
    SetMockTime(mockTime);
    CBlockIndex* block = nullptr;
    if (blockTime > 0) {
        LOCK(cs_main);
        auto inserted = chainman.BlockIndex().emplace(std::piecewise_construct, std::make_tuple(GetRandHash()), std::make_tuple());
        assert(inserted.second);
        const uint256& hash = inserted.first->first;
        block = &inserted.first->second;
        block->nTime = blockTime;
        block->phashBlock = &hash;
        state = TxStateConfirmed{hash, block->nHeight, 0};
    }
    return wallet.AddToWallet(MakeTransactionRef(tx), state, [&](CWalletTx& wtx, bool ) {
        
        
        
        wtx.m_state = state;
        return true;
    })->nTimeSmart;
}
BOOST_AUTO_TEST_CASE(ComputeTimeSmart)