diff --git a/src/nl/jeroenhoek/josm/gridify/ui/GridSizePanel.java b/src/nl/jeroenhoek/josm/gridify/ui/GridSizePanel.java
index 9fe81d0..da0e856 100644
--- a/src/nl/jeroenhoek/josm/gridify/ui/GridSizePanel.java
+++ b/src/nl/jeroenhoek/josm/gridify/ui/GridSizePanel.java
@@ -59,34 +59,36 @@ void flipRowsColumns() {
     }
 
     void setRowCount(int rows) {
-        if (rows < 1 || rows > 1000) return;
+        if (rows < PositiveSpinner.SPINNER_MIN_VALUE || rows > PositiveSpinner.SPINNER_MAX_VALUE) return;
         this.rows = rows;
         this.spinnerRows.setValue(rows);
         changeCallback.changed(getRowCount(), getColumnCount());
     }
 
     void setColumnCount(int columns) {
-        if (columns < 1 || columns > 1000) return;
+        if (columns < PositiveSpinner.SPINNER_MIN_VALUE || columns > PositiveSpinner.SPINNER_MAX_VALUE) return;
         this.columns = columns;
         this.spinnerColumns.setValue(columns);
         changeCallback.changed(getRowCount(), getColumnCount());
     }
 
     void nudgeRowCount(Nudge direction) {
-        if (direction == Nudge.INCREMENT || this.rows > 1) {
-            this.rows += direction == Nudge.INCREMENT ? 1 : -1;
-            this.spinnerRows.setValue(rows);
+        int newRows = this.rows + (direction == Nudge.INCREMENT ? 1 : -1);
+        if (newRows >= PositiveSpinner.SPINNER_MIN_VALUE && newRows <= PositiveSpinner.SPINNER_MAX_VALUE) {
+            this.rows = newRows;
+            this.spinnerRows.setValue(newRows);
             this.spinnerRows.caretToEnd();
-            changeCallback.changed(getRowCount(), getColumnCount());
+            changeCallback.changed(this.rows, this.columns);
         }
     }
 
     void nudgeColumnCount(Nudge direction) {
-        if (direction == Nudge.INCREMENT || this.columns > 1) {
-            this.columns += direction == Nudge.INCREMENT ? 1 : -1;
-            this.spinnerColumns.setValue(columns);
+        int newCols = this.columns + (direction == Nudge.INCREMENT ? 1 : -1);
+        if (newCols >= PositiveSpinner.SPINNER_MIN_VALUE && newCols <= PositiveSpinner.SPINNER_MAX_VALUE) {
+            this.columns = newCols;
+            this.spinnerColumns.setValue(newCols);
             this.spinnerColumns.caretToEnd();
-            changeCallback.changed(getRowCount(), getColumnCount());
+            changeCallback.changed(this.rows, this.columns);
         }
     }
 
diff --git a/src/nl/jeroenhoek/josm/gridify/ui/GridifySettingsDialog.java b/src/nl/jeroenhoek/josm/gridify/ui/GridifySettingsDialog.java
index 10afd5a..f653003 100644
--- a/src/nl/jeroenhoek/josm/gridify/ui/GridifySettingsDialog.java
+++ b/src/nl/jeroenhoek/josm/gridify/ui/GridifySettingsDialog.java
@@ -83,7 +83,7 @@ public GridifySettingsDialog(InputData inputData, GridifySettings settings) {
         constraints.insets = insetsIndent;
         controlPanel.add(gridSizePanel, constraints);
 
-        if (inputData.getSourceWay().isPresent()) {
+        inputData.getSourceWay().ifPresent(sourceWay -> {
             JLabel wayLabel = new JLabel(tr("Source way"));
             wayLabel.setBorder(underline);
             constraints.gridy = 4;
@@ -92,18 +92,18 @@ public GridifySettingsDialog(InputData inputData, GridifySettings settings) {
 
             // Always check the 'delete source way' option when a new way is used as template.
             // It tends to have been drawn specifically to cut up.
-            boolean deleteSourceWay = inputData.getSourceWay().get().isNew();
+            boolean deleteSourceWay = sourceWay.isNew();
 
             sourceWayPanel = new SourceWayPanel(
                     settings.copyTagsFromSource(),
                     deleteSourceWay || settings.deleteSource(),
-                    !inputData.getSourceWay().get().getReferrers().isEmpty(),
+                    !sourceWay.getReferrers().isEmpty(),
                     this::fireChangeEvent
             );
             constraints.gridy = 5;
             constraints.insets = insetsIndent;
             controlPanel.add(sourceWayPanel, constraints);
-        }
+        });
 
         JLabel statsLabel = new JLabel(tr("Statistics"));
         constraints.gridy = 6;
diff --git a/src/nl/jeroenhoek/josm/gridify/ui/PositiveSpinner.java b/src/nl/jeroenhoek/josm/gridify/ui/PositiveSpinner.java
index 5e2b56c..e530878 100644
--- a/src/nl/jeroenhoek/josm/gridify/ui/PositiveSpinner.java
+++ b/src/nl/jeroenhoek/josm/gridify/ui/PositiveSpinner.java
@@ -11,6 +11,7 @@
 import java.awt.Dimension;
 import java.awt.Font;
 import java.awt.event.FocusEvent;
+import java.text.ParseException;
 import java.util.Objects;
 
 /**
@@ -42,24 +43,19 @@ public PositiveSpinner(int defaultValue, ValueChanged changeCallback) {
 
         // Kind of weird that the default JSpinner doesn't do this.
         addMouseWheelListener(e -> {
-            int ticks = e.getWheelRotation();
-            Object newValue = null;
-            if (ticks > 0) {
-                for (int tick = 0; tick < ticks; tick++) {
-                    Object previous = getPreviousValue();
-                    if (previous == null) break;
-                    newValue = previous;
-                }
-            } else if (ticks < 0) {
-                for (int tick = 0; tick > ticks; tick--) {
-                    Object next = getNextValue();
-                    if (next == null) break;
-                    newValue = next;
-                }
+            try {
+                commitEdit();
+            } catch (ParseException ignore) {
             }
+            int ticks = e.getWheelRotation();
+            int current = (Integer) getValue();
+
+            // e.getWheelRotation() is positive when scrolling down (decrease) and negative when scrolling up (increase)
+            int newValue = Math.max(SPINNER_MIN_VALUE, Math.min(SPINNER_MAX_VALUE, current - ticks));
 
-            if (newValue != null) {
+            if (newValue != current) {
                 setValue(newValue);
+                caretToEnd();
             }
         });
 
@@ -88,27 +84,30 @@ public void changedUpdate(DocumentEvent e) {
     }
 
     void callbackIfChanged() {
-        Integer newValue;
+        String text = field.getText();
+        if (text.isBlank()) {
+            return;
+        }
+
+        int newValue;
         try {
-            newValue = Integer.parseInt(field.getText());
+            newValue = Integer.parseInt(text);
         } catch (NumberFormatException e) {
-            // Ignore.
             return;
         }
 
         if (!Objects.equals(newValue, lastValue)) {
-            SwingUtilities.invokeLater(() -> {
-                this.lastValue = newValue;
-                changeCallback.onChange(newValue);
-            });
+            this.lastValue = newValue;
+            SwingUtilities.invokeLater(() -> changeCallback.onChange(newValue));
         }
     }
 
     @Override
     public void setValue(Object value) {
-        // No need to update the value if nothing changes. This prevents the caret being placed at an awkward position.
-        if (Objects.equals(value, lastValue)) return;
+        // Check against the actual model value instead of lastValue so the model doesn't get stuck.
+        if (Objects.equals(value, getValue())) return;
 
+        this.lastValue = (Integer) value;
         super.setValue(value);
     }