HiIt would appear the truck is following standard practice of windows behavior.
Hope someone can shed some light, for some reason the form resize is not being fired while the form is being resized.
It appears as the form.resize is acting like a resizeend event.
the attached project tries to keep the form to an aspet ration of 16:9; which it only does when you release the mouse; which makes it impossible for a user to adjust its dimensions.
Lazarus 2.3.0 r65271 FPC 3.3.1 x86_64-win64-win32/win64
okay with Lazarus 2.1.0 r63084 FPC 3.3.1 x86_64-win64-win32/win64