In solution explorer expand your form out so you see the designer, resx and class. It's a triangle you click in vs2015, might be a + in vs2013 - the thing to the left of the form anyhow.
Double click your form.designer.cs file in visual studio and take a look at all the code which builds your form.
Your original chart will be in there but something will be wrong with it.
It'll be hidden, size 0 or something.
If you can't figure it out then grab your code behind and save a copy in notepad or something.
In fact, back up your entire solution. Zip it or something.
In your solution, strip it all back to like
public partial class Form2 : Form
{
public Form2()
{
InitializeComponent();
}
Remove all references to your chart1 in that designer code.
Make sure it compiles OK.
Drag another chart onto your designer as a chart1 replacement.
Make sure you still see that when you close and re-open visual studio.
This is to ensure that it's not visual studio is broke.
Then add your code behind back in.
Do it piece by piece and take a look at each piece, just in case there's something bad in there you overlooked.
Good luck.
