fix: move focused_tab if >= removed index

If the focused tab index is before the removed tab index,
then it must not change, if it is equal or after, because
all the elements are moved to the left, the focused tab
index must be decremented with 0 as minimum.

liana-gui/src/gui/pane.rs

@@ -71,13 +71,11 @@ impl Pane {
             return None;
         }
         let tab = self.tabs.remove(i);
-        self.focused_tab = if self.tabs.is_empty() {
-            0
-        } else if i < self.tabs.len() - 1 {
-            i
-        } else {
-            self.tabs.len() - 1
-        };
+
+        if self.focused_tab >= i {
+            self.focused_tab = self.focused_tab.saturating_sub(1);
+        }
+
         Some(tab)
     }