Automatic transitions don't resize correctly when setting End via properties

[JamesRichards22]

Describe the bug: I am using OpenShot-v3.4.0-release-candidate-14762-0932af2c-0b018e34 and if I create a transition by dragging one clip over another, and then try and resize the transition using the property editor and set the End value, then the transition resizes, but the Brightness end keyframe doesn't move with it. The end keyframe stays where it was.

If you only use the mouse to change the size, it works. But I like to set it to exactly 0.5 seconds.

The workaround is the set in preferences the default size and drag a transition from the Transitions tab.

This has been happening since at least build 14724.

Steps to reproduce the behavior:

1. On a timeline with 2 clips, drag one clip over another with at least 0.5 seconds overlap to create a Transition

2. Click on the Transition

3. Click on the Properties tab

4. Note the Brightness Keyframe values go from 1 on the first Keyframe, to -1 for the last Keyframe in Properties

5. Double Click on End in Properties to edit it

6. Set End value to 0.5

7. Click on the final Keyframe for the Transition

Expected behavior: The Brightness property for the 2nd keyframe changes to -1.000

Actual behavior: The 2nd Brightness keyframe property does not adjust to the new size.

System Details:

{
    "build_name": "OpenShot-v3.4.0-release-candidate-14762-0932af2c-0b018e34",
    "date": "2025-11-02 20:36",
    "libopenshot": {
        "CI_COMMIT_REF_NAME": "release-20250612",
        "CI_COMMIT_SHA": "0932af2c1ed77663b0af6d0761525b78524506b5",
        "CI_JOB_ID": "46101",
        "CI_PIPELINE_ID": "14710",
        "CI_PROJECT_NAME": "libopenshot",
        "SO": "28",
        "VERSION": "0.5.0"
    },
    "libopenshot-audio": {
        "CI_COMMIT_REF_NAME": "release-20250612",
        "CI_COMMIT_SHA": "0b018e347c7973e4253e29ec41394f3dfa87df4d",
        "CI_JOB_ID": "43309",
        "CI_PIPELINE_ID": "13911",
        "CI_PROJECT_NAME": "libopenshot-audio",
        "SO": "10",
        "VERSION": "0.5.0"
    },
    "openshot-qt": {
        "CI_COMMIT_REF_NAME": "release-20250612",
        "CI_COMMIT_SHA": "b7a809e80d7eab181a09627742f6aaebdc7a4613",
        "CI_JOB_ID": "46341",
        "CI_PIPELINE_ID": "14762",
        "CI_PROJECT_NAME": "openshot-qt",
        "SO": null,
        "VERSION": "3.4.0"
    }
}

Log Files: Console output from AppImage has

INFO properties_model: end for 47F13OG0LH changed to 0.5 at frame 1 with interpolation: -1 at closest x: -1
INFO properties_model: Item 47F13OG0LH: changed end to 0.5 at frame 1 (x: -1)

[Colorjet3]

Hello @JamesRichards22 Thank you for the detailed information. I am able to replicate this issue in my Windows 11 Pro environment as well. I am going to submit this to the bug queue for the lead developer to fix it.