Column widths of Expressions window resets on debugger restart

Steps to reproduce:

• Start debugging and break
• Add an expression to the Expressions window
• Continue debugging and let the debuggee stop normally
• Restart debugging and run to the breakpoint

Actual behavior:

• The Expressions column widths are reset to their default values

Expected behavior:

• The column widths stay the same, as it already works for the Locals window