I'm placing controls on a TabPage of a TabControl which has it's anchor set to Top, Right, Bottom, Left.
I set the Anchor of any Control within that TabPage to Top, Right.
Every time I open the design view of the form, the Controls move roughly the width of the form to the left OR their size is wiped out to 0,0. Each re-load causes the Controls to jump left again as their Location Left becomes an ever increasing negative value.
This problem has only existed since adding a UserControl to another Tab within the Same TabControl.
If I set the anchor of the Control to Top, Left, the problem goes away, except for the fact I can never position the controls where I need them other than programmatically, which is a pain and makes the code quite cryptic.
This bug was mentioned in a previous post and has clearly existed in VS for a decade or so. It has already been asked here: How to resolve Windows Forms designer issue - controls move on debug? but the answer didn't 'fix' the underlying problem, it was just a workaround.
I'm using VS2019 and it's a .Net 4.6.1 C# Winforms application.
Just for completeness. The issue here turned out to be using Anchored UserControls inside a TabControl. I ended up moving the content of the tab to a Modal Form. Not idea but stopped the problem happening.