Hi...
An OK button isn't required in the Sprite Editor.
When you use the Sprite Editor in "Stage Mode", any changes you make will add a keyframe on the Timeline. So, for example, if a sprite was red at frame 1 and at frame 100 you chose a blue sprite, you would see that result when you played back the project because the keys would be on the Timeline.
However, when you use the Sprite Editor in Composer mode you instead have the options to Add New Sprite, Replace Current Sprite, Delete and Horizontal Flip. So, in this case if you want the sprite change to be permanent, you can use Replace Current Sprite and then when you return to Stage Mode the new sprite will have replaced the old one.
Peter
Forum Administrator
www.reallusion.com