Fix an issue with frozen column count and unhiding. (#11929) (#11932)

* Fix an issue with frozen column count and unhiding.

Unhiding logic should take into account that there can be hidden frozen
columns that are not the column currently getting shown.

client/src/main/java/com/vaadin/client/widgets/Grid.java

@@ -5336,7 +5336,9 @@ public class Grid<T> extends ResizeComposite implements HasSelectionHandlers<T>,
                     int escalatorFrozenColumns = grid.escalator
                             .getColumnConfiguration().getFrozenColumnCount();
                     if (gridFrozenColumns > escalatorFrozenColumns
-                            && escalatorFrozenColumns == columnIndex) {
+                            && escalatorFrozenColumns == columnIndex
+                            && grid.getColumns()
+                                    .indexOf(this) < gridFrozenColumns) {
                         grid.escalator.getColumnConfiguration()
                                 .setFrozenColumnCount(++escalatorFrozenColumns);
                     }

uitest/src/main/java/com/vaadin/tests/components/grid/GridUnhideColumnsWithFrozen.java

@@ -0,0 +1,40 @@
+package com.vaadin.tests.components.grid;
+
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.tests.components.AbstractTestUI;
+import com.vaadin.ui.Component;
+import com.vaadin.ui.Grid;
+import com.vaadin.ui.Label;
+
+public class GridUnhideColumnsWithFrozen extends AbstractTestUI {
+
+    @Override
+    protected void setup(VaadinRequest request) {
+        Grid<Integer> grid = new Grid<>();
+        for (int i = 0; i < 15; i++) {
+            String columnId = String.valueOf(i);
+            Grid.Column<Integer, Component> column = addColumn(grid, columnId);
+            column.setHidable(true);
+            if (i == 3 || i == 4) {
+                column.setHidden(true);
+            }
+            column.setCaption(columnId);
+            column.setId(columnId);
+        }
+        grid.setFrozenColumnCount(4);
+        grid.setItems(0);
+        addComponent(grid);
+    }
+
+    private Grid.Column<Integer, Component> addColumn(Grid<Integer> grid,
+            String columnId) {
+        return grid.addComponentColumn(i -> new Label(columnId));
+    }
+
+    @Override
+    protected String getTestDescription() {
+        return "Columns 0-3 have been set frozen, unhiding column 4 before column 3"
+                + " should not make column 4 frozen.";
+    }
+
+}

uitest/src/test/java/com/vaadin/tests/components/grid/GridUnhideColumnsWithFrozenTest.java

@@ -0,0 +1,38 @@
+package com.vaadin.tests.components.grid;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.List;
+
+import org.junit.Test;
+import org.openqa.selenium.By;
+import org.openqa.selenium.WebElement;
+
+import com.vaadin.testbench.elements.GridElement;
+import com.vaadin.tests.tb3.SingleBrowserTest;
+
+public class GridUnhideColumnsWithFrozenTest extends SingleBrowserTest {
+
+    @Test
+    public void visibleFrozenColumnCount() {
+        openTestURL();
+
+        GridElement grid = $(GridElement.class).first();
+        List<WebElement> frozen = grid.getHeader()
+                .findElements(By.className("frozen"));
+        assertEquals("Unexpected frozen column count before unhiding", 3,
+                frozen.size());
+
+        grid.findElement(By.className("v-grid-sidebar-button")).click();
+        List<WebElement> hidden = findElement(
+                By.className("v-grid-sidebar-content"))
+                        .findElements(By.className("hidden"));
+        assertEquals("Unexpected amount of hidden columns", 2, hidden.size());
+        assertEquals("Unexpected hidden column", "4", hidden.get(1).getText());
+        hidden.get(1).click();
+
+        frozen = grid.getHeader().findElements(By.className("frozen"));
+        assertEquals("Unexpected frozen column count after unhiding", 3,
+                frozen.size());
+    }
+}