qt: Make SendCoinsEntry aware of runtime palette change

This change fixes the GUI when changing appearance on macOS.

src/qt/sendcoinsentry.cpp

@@ -236,6 +236,19 @@ void SendCoinsEntry::updateDisplayUnit()
     }
 }
 
+void SendCoinsEntry::changeEvent(QEvent* e)
+{
+#ifdef Q_OS_MACOS
+    if (e->type() == QEvent::PaletteChange) {
+        ui->addressBookButton->setIcon(platformStyle->SingleColorIcon(QStringLiteral(":/icons/address-book")));
+        ui->pasteButton->setIcon(platformStyle->SingleColorIcon(QStringLiteral(":/icons/editpaste")));
+        ui->deleteButton->setIcon(platformStyle->SingleColorIcon(QStringLiteral(":/icons/remove")));
+        ui->deleteButton_is->setIcon(platformStyle->SingleColorIcon(QStringLiteral(":/icons/remove")));
+        ui->deleteButton_s->setIcon(platformStyle->SingleColorIcon(QStringLiteral(":/icons/remove")));
+    }
+#endif
+}
+
 bool SendCoinsEntry::updateLabel(const QString &address)
 {
     if(!model)

src/qt/sendcoinsentry.h

@@ -69,6 +69,9 @@ private Q_SLOTS:
     void on_pasteButton_clicked();
     void updateDisplayUnit();
 
+protected:
+    void changeEvent(QEvent* e) override;
+
 private:
     SendCoinsRecipient recipient;
     Ui::SendCoinsEntry *ui;