History: fix payment proof button

Adding support for reserve proof added an additional
argument to the getProofClicked signal. The payment
proof button on the transaction list from history.qml
does not pass this argument and fails with insufficient
argument error.

Fixes: 0f67580e ("Advanced: ReserveProof: Add support for reserve proof")

1 files changed, 1 insertions, 1 deletions

diff --git a/main.qml b/main.qml
index 18249c7b..de280b56 100644
--- a/main.qml
+++ b/main.qml
@@ -999,7 +999,7 @@ ApplicationWindow {
 
     // called on "getProof"
     function handleGetProof(txid, address, message, amount) {
-        if (amount.length > 0) {
+        if (amount !== null && amount.length > 0) {
             var result = currentWallet.getReserveProof(false, currentWallet.currentSubaddressAccount, walletManager.amountFromString(amount), message)
             txProofComputed(null, result)
         } else {