It's hard to explain this properly in the title. If I enter the trim mode on an edit point between two clips on Final Cut Pro 7, it opens up the side by side view with the final frame of the preceding clip on the left and the first frame of the following clip on the right. If I then perform a ripple trim to one of the two windows left or right it occasionally though not always produces an unexpected behaviour; while performing the adjustment, either by using > and < keys, or playing back to the desired point and hitting k, the trim is performed as desired but as soon as I stop hitting > or have pressed k, the frame on the adjusted clip in the trim window is incorrect and is not the frame on which I stopped or which is at the edit point when viewed from timeline or in the preview.
It does not display the frame which I chose as the new edit point during the trimming operation but instead some other seemingly random point within the clip that was being adjusted, I don't know if there's anything predictable about which frame it chooses, maybe it's the beginning or end frame of the entire source clip (disregarding my in and out points) or maybe it really is random but the point is it isn't the frame on which I've chosen to perform the trim which makes it very difficult to use the trim mode as intended because I may choose a trim point, preview it and then decided I need to add or remove a few frames to make a better match cut. Without the visual reference of the correct end frame of the preceding clip or correct beginning frame of the following clip, I can't judge where two points in action best meet to make an accurate match cut which would be the main reason in my mind for using the trim window. Instead I have to guess, or exit trim mode and start the process again only to have it messed up again by this glitch.
Any idea what Final Cut is doing here? Is it a glitch or a function of how it works that I've failed to grasp?