diff --git a/src/nostalgia/core/studio/tilesheeteditormodel.cpp b/src/nostalgia/core/studio/tilesheeteditormodel.cpp
index 91261b1e..b692a972 100644
--- a/src/nostalgia/core/studio/tilesheeteditormodel.cpp
+++ b/src/nostalgia/core/studio/tilesheeteditormodel.cpp
@@ -19,7 +19,6 @@ void TileSheetEditorModel::draw(const geo::Point &pt, std::size_t palIdx) noexce
 		m_updated = m_ongoingDrawCommand->append(ptToIdx(pt, m_img.columns));
 	} else {
 		pushCommand(new DrawCommand(&m_img, ptToIdx(pt, m_img.columns), palIdx));
-		m_updated = true;
 	}
 }
 
@@ -70,6 +69,7 @@ void TileSheetEditorModel::getFillPixels(bool *pixels, const geo::Point &pt, int
 void TileSheetEditorModel::pushCommand(studio::UndoCommand *cmd) noexcept {
 	m_undoStack.push(cmd);
 	m_ongoingDrawCommand = dynamic_cast<DrawCommand*>(cmd);
+	m_updated = true;
 }
 
 }
\ No newline at end of file
diff --git a/src/nostalgia/core/studio/tilesheeteditormodel.hpp b/src/nostalgia/core/studio/tilesheeteditormodel.hpp
index 04cedeca..22bee50a 100644
--- a/src/nostalgia/core/studio/tilesheeteditormodel.hpp
+++ b/src/nostalgia/core/studio/tilesheeteditormodel.hpp
@@ -68,9 +68,15 @@ struct DrawCommand: public studio::UndoCommand {
 
 		constexpr bool append(std::size_t idx) noexcept {
 			if (m_changes.back().value.idx != idx) {
-				m_changes.emplace_back(idx, m_img->pixels[idx]);
-				m_img->setPixel(idx, m_palIdx);
-				return true;
+				// duplicate entries are bad
+				auto existing = std::find_if(m_changes.cbegin(), m_changes.cend(), [idx](const auto &c) {
+					return c.idx == idx;
+				});
+				if (existing == m_changes.cend()) {
+					m_changes.emplace_back(idx, m_img->pixels[idx]);
+					m_img->setPixel(idx, m_palIdx);
+					return true;
+				}
 			}
 			return false;
 		}