How to reproduce:

• Change column sizes of the certificate list in the main window
• Open a new tab; the new tab will inherit the column sizes from the previously shown tab
• Reload the key list (e.g. with F5)

Expected result: The column sizes don't change.
Actual result: The column sizes are reset to the default.

Note: Importing keys also triggers a change of the key list and therefore a reset of the column sizes of newly opened tabs. This was first noticed while testing T7008: Kleopatra: New tabs in certficate list should use same column layout as current tab.