Index: ActiviteitenOpvolging/ActiviteitenOpvolging/grids/IMainForm.vb
===================================================================
diff -u -r1682 -r1701
--- ActiviteitenOpvolging/ActiviteitenOpvolging/grids/IMainForm.vb	(.../IMainForm.vb)	(revision 1682)
+++ ActiviteitenOpvolging/ActiviteitenOpvolging/grids/IMainForm.vb	(.../IMainForm.vb)	(revision 1701)
@@ -6,4 +6,11 @@
     ''' <param name="gridNumber">The index of the grid, 0 based</param>
     ''' <returns>A list containing all work items</returns>
     Function GetWorkItems(gridNumber As Integer) As List(Of IWorkItem)
+
+    ''' <summary>
+    ''' A different activity was selected in the grid.
+    ''' </summary>
+    ''' <param name="activity">The activity. Nothing means no activity was selected.</param>
+    ''' <param name="gridNumber">The number of the grid</param>
+    sub ChangeSelectedActivity(activity As IActivity, gridNumber As Integer)
 End Interface
Index: ActiviteitenOpvolging/ActiviteitenOpvolging/ActiviteitenOpvolging.vbproj
===================================================================
diff -u -r1696 -r1701
--- ActiviteitenOpvolging/ActiviteitenOpvolging/ActiviteitenOpvolging.vbproj	(.../ActiviteitenOpvolging.vbproj)	(revision 1696)
+++ ActiviteitenOpvolging/ActiviteitenOpvolging/ActiviteitenOpvolging.vbproj	(.../ActiviteitenOpvolging.vbproj)	(revision 1701)
@@ -94,7 +94,7 @@
     <Compile Include="grids\custom controls\BorderCell.vb" />
     <Compile Include="grids\custom controls\BorderedTextFigureCell.vb" />
     <Compile Include="grids\IMainForm.vb" />
-    <Compile Include="grids\IUserControl.vb" />
+    <Compile Include="grids\IDataGridUserControl.vb" />
     <Compile Include="mappers\CacheMapper.vb" />
     <Compile Include="My Project\AssemblyInfo.vb" />
     <Compile Include="My Project\Application.Designer.vb">
Index: ActiviteitenOpvolging/ActiviteitenOpvolging/ActiviteitenOpvolgingForm.vb
===================================================================
diff -u -r1693 -r1701
--- ActiviteitenOpvolging/ActiviteitenOpvolging/ActiviteitenOpvolgingForm.vb	(.../ActiviteitenOpvolgingForm.vb)	(revision 1693)
+++ ActiviteitenOpvolging/ActiviteitenOpvolging/ActiviteitenOpvolgingForm.vb	(.../ActiviteitenOpvolgingForm.vb)	(revision 1701)
@@ -47,12 +47,28 @@
             _userControls.Add(userControl)
             'Add to layout panel.
             DatagridViewControlsFlowLayoutPanel.Controls.Add(userControl)
+            'CLear selection on every data grid view.
+            ChangeSelectedActivity(Nothing, 0)
         Next
     End Sub
 
     ''' <inheritdoc/>
-    Public Function GetWorkItems(gridNumber As Integer) As List(Of IWorkItem)Implements IMainForm.GetWorkItems
+    Public Function GetWorkItems(gridNumber As Integer) As List(Of IWorkItem) Implements IMainForm.GetWorkItems
         Return _workItemManager.GiveWorkItems(gridNumber)
     End Function
 
+    ''' <inheritdoc/>
+    Public Sub ChangeSelectedActivity(activity As IActivity, gridNumber As Integer) Implements IMainForm.ChangeSelectedActivity
+        'If the activity is Nothing, no activity was selected, meaning that everything should be cleared.
+        If activity Is Nothing Then
+            'Clear selection for every grid user control.
+            _userControls.ForEach(Sub(userControl) userControl.RemoveSelection())
+        Else
+            'Clear selection of every grid except the one with the grid number.
+            For each control in _userControls
+                'Remove selection from every other grid.
+                if not control.GridNumber = gridNumber Then control.RemoveSelection()
+            Next
+        End If
+    End Sub
 End Class
FishEye: Tag 1701 refers to a dead (removed) revision in file `ActiviteitenOpvolging/ActiviteitenOpvolging/grids/IUserControl.vb'.
FishEye: No comparison available.  Pass `N' to diff?
Index: ActiviteitenOpvolging/ActiviteitenOpvolging/grids/IDataGridUserControl.vb
===================================================================
diff -u
--- ActiviteitenOpvolging/ActiviteitenOpvolging/grids/IDataGridUserControl.vb	(revision 0)
+++ ActiviteitenOpvolging/ActiviteitenOpvolging/grids/IDataGridUserControl.vb	(revision 1701)
@@ -0,0 +1,12 @@
+Public Interface IDataGridUserControl
+    ''' <summary>
+    ''' Clears the selection from the datagrid.
+    ''' </summary>
+    sub RemoveSelection()
+
+    ''' <summary>
+    ''' Access to the grid number.
+    ''' </summary>
+    ''' <returns></returns>
+    ReadOnly Property GridNumber As Integer
+End Interface
Index: ActiviteitenOpvolging/ActiviteitenOpvolging/grids/DataGridViewUserControl.vb
===================================================================
diff -u -r1700 -r1701
--- ActiviteitenOpvolging/ActiviteitenOpvolging/grids/DataGridViewUserControl.vb	(.../DataGridViewUserControl.vb)	(revision 1700)
+++ ActiviteitenOpvolging/ActiviteitenOpvolging/grids/DataGridViewUserControl.vb	(.../DataGridViewUserControl.vb)	(revision 1701)
@@ -3,8 +3,9 @@
 Public Class DataGridViewUserControl
     Implements IDataGridUserControl
     Private ReadOnly _parentForm As IMainForm
-    Private ReadOnly _gridNumber As Integer
+    Public ReadOnly Property GridNumber As Integer Implements IDataGridUserControl.GridNumber
 
+
     Sub New()
         ' This call is required by the designer.
         InitializeComponent()
@@ -26,9 +27,14 @@
         _parentForm = parentForm
 
         'Grid number.
-        _gridNumber = gridNumber
+        Me.GridNumber = gridNumber
     End Sub
 
+    ''' <inheritdoc/>
+    Public Sub RemoveSelection() Implements IDataGridUserControl.RemoveSelection
+        _WorkItemsDataGridView.ClearSelection()
+    End Sub
+
     Private Sub DataGridViewUserControl_Load(sender As Object, e As EventArgs) Handles MyBase.Load
         Try
             'Set back color and fore color.
@@ -64,7 +70,7 @@
             WorkItemsDataGridView.RowTemplate.Height = 30 'todo configureerbaar maken
 
             'Set label.
-            GridLabel.Text = ConfigsLoader.GridLabelNames(_gridNumber)
+            GridLabel.Text = ConfigsLoader.GridLabelNames(GridNumber)
 
             'Load the data.
             LoadData()
@@ -112,7 +118,7 @@
     ''' Update the header text and visibility of the static columns.
     ''' </summary>
     Private Sub UpdateStaticColumns()
-        Dim names = ConfigsLoader.GridColumnHeaderNames().Item(_gridNumber)
+        Dim names = ConfigsLoader.GridColumnHeaderNames().Item(GridNumber)
         For i = 0 To names.Count() - 1
             'Fetch name.
             Dim headerText = names(i)
@@ -136,7 +142,7 @@
     ''' </summary>
     Private Sub LoadWorkItems()
         Try
-            _workItems = _parentForm.GetWorkItems(_gridNumber)
+            _workItems = _parentForm.GetWorkItems(GridNumber)
         Catch ex As Exception
             Throw New Exception($"Could not load work items.{vbNewLine}{ex.Message}")
         End Try
@@ -306,8 +312,8 @@
             'Disable click on columns or cell that should not be clicked on.
             'Check columns, only activity columns should be able to be clicked on.
             If Not WorkItemsDataGridView.Columns(WorkItemsDataGridView.CurrentCell.ColumnIndex).Name.Contains("ActivityColumn") Then
-                'Column is not that of an activity. Remove selection.
-                WorkItemsDataGridView.ClearSelection()
+                'Column is not that of an activity
+                _parentForm.ChangeSelectedActivity(Nothing, GridNumber)
                 Return
             End If
 
@@ -321,14 +327,16 @@
             If activity.Status = ActivityStateEnum.Finished Or
                activity.Status = ActivityStateEnum.Zero Or
                     activity.IsReadOnly Then
-                'If equal to one of those, remove selection.
-                WorkItemsDataGridView.ClearSelection()
+                'If equal to one of those, the selection is not valid.
+                _parentForm.ChangeSelectedActivity(Nothing, GridNumber)
+            Else
+                'Selection was valid.
+                _parentForm.ChangeSelectedActivity(activity, GridNumber)
             End If
         Catch ex As Exception
             MessageBox.Show($"Could not select a cell in {Me.Name}.{vbNewLine}{ex.Message}", "An error occured...", MessageBoxButtons.OK, MessageBoxIcon.Error)
             'Remove selection.
             WorkItemsDataGridView.ClearSelection()
         End Try
     End Sub
-
 End Class