In Windows (all versions) programs often a highlighted button is the default for the Enter key.
In PSP X4 through to X7 this fails for some adjustments and effects.
To illustrate, here are three images that require different Levels adjustments.

When I set up the Level adjustment (Adjust > Brightness and Contrast > Levels or as in my case clicking a customised Levels button on a toolbar) I get the following dialog box where the OK Button is clearly highlighted as the default action.

However hitting the Enter key does not accept and apply that action. Either the image flashes or nothing happens. If you do the Brightness and Contrast or the Red/Green/Blue adjustment then hitting the Enter key does finish the action.
Sometimes the Enter key will do the same as the reset button and just set the sliders back to their default positions.

The Enter Key Default action fails for Levels, Hue Saturation and Lightness (Shift H),
For Threshold, Vibrancy, BackLighting Fill Flash the Enter key will only apply the action after an adjustment has been made so no good for remembering the same value and applying it to multiple images quickly. In all cases you are forced to move the cursor to the OK button and click that. This requires extra movement and time.
Some of the Effects are also not working with teh Enter key as well but I will not list those at present.
In X2 and earlier the Enter key does apply the Levels adjustment and can be used from image to image quickly-
so - click Levels button, Enter, Click X to close image, Enter,// next Image- click Levels, Enter, Click Close, Enter then becomes
Click Levels , click OK, Click Close, Enter, next image, Click Levels, Click OK, Click Close, Enter
This is an extra move of the cursor to the OK button and click per image and when I am working on 100s of images in a session any simplification saves time.
As well, fixing this will maintain consistency in the application of actions.
Can others verify the failure of the Enter key with their versions of PSP and systems
