Handle preview without file path

certy.ps1

@@ -60,6 +60,7 @@ function Get-FilePreview {
         [int]$MaxLines = 200
     )
 
+    if ([string]::IsNullOrWhiteSpace($Path)) { return "" }
     if (-not (Test-Path -Path $Path -PathType Leaf)) { return "" }
     try {
         $lines = Get-Content -Path $Path -TotalCount $MaxLines -ErrorAction Stop
@@ -849,9 +850,21 @@ $replicationEnabledBox.Add_CheckedChanged({
 })
 
 $filePreviewBtn.Add_Click({
-    $filePreviewBox.Text = Get-FilePreview -Path $fileBox.Text.Trim()
-    if (Test-Path -Path $fileBox.Text.Trim() -PathType Leaf) {
-        $fileHosts = Get-Content -Path $fileBox.Text.Trim() | ForEach-Object { $_.Trim() } | Where-Object { $_ }
+    $path = $fileBox.Text.Trim()
+    if ([string]::IsNullOrWhiteSpace($path)) {
+        $previewHosts = Split-List $hostsBox.Text
+        if ($previewHosts.Count -gt 0) {
+            $filePreviewBox.Text = ($previewHosts | Select-Object -First 200) -join [Environment]::NewLine
+            return
+        }
+        $filePreviewBox.Text = ""
+        & $logAction "No file selected and no hostnames to preview."
+        return
+    }
+
+    $filePreviewBox.Text = Get-FilePreview -Path $path
+    if (Test-Path -Path $path -PathType Leaf) {
+        $fileHosts = Get-Content -Path $path | ForEach-Object { $_.Trim() } | Where-Object { $_ }
         $zoneGuess = Get-CommonZoneFromHosts -Hosts $fileHosts
         if ($zoneGuess) {
             $zoneBox.Text = $zoneGuess