fix psbts panel: keep list of psbts in background

fix this comment:
#959 (comment)

new_preselected is changed for a preselect method that keeps the
current state of the psbts list panel and open the modal with the
selected psbt.

Author: edouardparis

gui/src/app/mod.rs

@@ -161,7 +161,7 @@ impl App {
                     .list_spend_transactions(Some(&[*txid]))
                     .map(|txs| txs.first().cloned())
                 {
-                    self.panels.psbts = PsbtsPanel::new_preselected(self.wallet.clone(), spend_tx);
+                    self.panels.psbts.preselect(spend_tx);
                     self.panels.current = menu;
                     return Command::none();
                 };

gui/src/app/state/psbts.rs

@@ -34,16 +34,11 @@ impl PsbtsPanel {
         }
     }
 
-    pub fn new_preselected(wallet: Arc<Wallet>, spend_tx: SpendTx) -> Self {
-        let psbt_state = psbt::PsbtState::new(wallet.clone(), spend_tx.clone(), true);
-
-        Self {
-            wallet,
-            spend_txs: vec![spend_tx],
-            warning: None,
-            selected_tx: Some(psbt_state),
-            import_tx: None,
-        }
+    pub fn preselect(&mut self, spend_tx: SpendTx) {
+        let psbt_state = psbt::PsbtState::new(self.wallet.clone(), spend_tx.clone(), true);
+        self.selected_tx = Some(psbt_state);
+        self.warning = None;
+        self.import_tx = None;
     }
 }