diff --git a/core/dialog_export.cpp b/core/dialog_export.cpp
index 03412cd14..78e90d656 100644
--- a/core/dialog_export.cpp
+++ b/core/dialog_export.cpp
@@ -232,7 +232,7 @@ void DialogExport::OnChange(wxCommandEvent &event) {
 // Move up
 void DialogExport::OnMoveUp(wxCommandEvent &event) {
 	int pos = FilterList->GetSelection();
-	if (pos == 0) return;
+	if (pos <= 0) return;
 	FilterList->Freeze();
 	wxString tempname = FilterList->GetString(pos);
 	bool tempval = FilterList->IsChecked(pos);
@@ -250,7 +250,7 @@ void DialogExport::OnMoveUp(wxCommandEvent &event) {
 void DialogExport::OnMoveDown(wxCommandEvent &event) {
 	int pos = FilterList->GetSelection();
 	int n = FilterList->GetCount();
-	if (pos == n-1) return;
+	if (pos == n-1 || pos == -1) return;
 	FilterList->Freeze();
 	wxString tempname = FilterList->GetString(pos);
 	bool tempval = FilterList->IsChecked(pos);
diff --git a/core/subs_grid.cpp b/core/subs_grid.cpp
index e86ad9de3..6afa3452e 100644
--- a/core/subs_grid.cpp
+++ b/core/subs_grid.cpp
@@ -959,8 +959,8 @@ void SubtitlesGrid::DuplicateLines(int n1,int n2,bool nextFrame) {
 		// Shift to next frame
 		if (nextFrame) {
 			int posFrame = VFR_Output.GetFrameAtTime(cur->End.GetMS(),false) + 1;
-			cur->Start.SetMS(VFR_Output.GetFrameAtTime(posFrame,true));
-			cur->End.SetMS(VFR_Output.GetFrameAtTime(posFrame,false));
+			cur->Start.SetMS(VFR_Output.GetTimeAtFrame(posFrame,true));
+			cur->End.SetMS(VFR_Output.GetTimeAtFrame(posFrame,false));
 			cur->UpdateData();
 		}