Check for null and invalid layout index
MODIFY
WalletWasabi.Fluent/Controls/ResponsivePanelState.cs
WalletWasabi.Fluent/Controls/ResponsivePanelState.cs
@@ -102,8 +102,8 @@ namespace WalletWasabi.Fluent.Controls
var element = GetItemAt(i);
var columnSpanPropertyValue = ResponsivePanel.GetColumnSpan((Control) element);
var rowSpanPropertyValue = ResponsivePanel.GetRowSpan((Control) element);
- var columnSpan = columnSpanPropertyValue[layoutIndex];
- var rowSpan = rowSpanPropertyValue[layoutIndex];
+ var columnSpan = columnSpanPropertyValue is not null && columnSpanPropertyValue.Count - 1 >= layoutIndex ? columnSpanPropertyValue[layoutIndex] : 1;
+ var rowSpan = rowSpanPropertyValue is not null && rowSpanPropertyValue.Count - 1 >= layoutIndex ? rowSpanPropertyValue[layoutIndex] : 1;
items[i] = new Item()
{

Check for null and invalid layout index