Private Sub customSplitter_PreviewMouseMove(sender As Object, e As MouseEventArgs) Handles MyBase.PreviewMouseMove _originPoint = e.GetPosition(Window.GetWindow(Me)) Private Sub customSplitter_MouseDown(sender As Object, e As MouseButtonEventArgs) Handles MyBase.MouseDown Public Property MinimumDistanceFromEdge As Integer Public Property SplitterDirection As SplitterDirectionEnum I created a custom grid splitter class that will not allow the grid splitter to go off the edge of a window (either the bottom or the side). This is what I can think of mate, hope I've been of some help. Handle a mixture of DragEnter and PreviewMouseMove events on the GridSplitter, keeping track of focus, and cancelling (e.Handled = true) the event when a certain size is reached.Add another row in the 3rd position which is * sized, and have your border on row 3 with a RowSpan of 2 (so the 3rd row is the one being really resized, and your 4th row isn't touched.Therefore if a GridSplitter is sandwiched between two * sized rows/columns, then it would implicitly respect your MinHeight, since in reality, it would not be touching it.When sized to Auto, a row/column will always resize according to its content, not bigger, and not smaller.

In reality, your MinHeight IS being respected, but so is the GridSplitter's request to grow being respected, which results in the Grid growing larger than your Window.A GridSplitter will always work on directly adjacent rows/columns.This is due to how the GridSplitter works. The way your code is, this cannot be done mate. Given the below XAML, how do I have the gridsplitter respect the MinHeight given to the 3rd row and have the content remain inside my window?

Instagram grid splitter