@Phelan-Kane
Hmm, it works here with this mini snippet:
HiseSnippet 1861.3oc2Y8taabiDmqk4cQN8ZaRS+KvcXgQ+fRu.CKaGmDTTTYKamJT6XEK0zqsenfZWJIhrK4VtbcsuhBberOUsEnu.Enu.2iv8Fb2vkqzxUVRVV0N04zGDDGxYleb3ry7iqZJEdz3XgD4rT6SinHmWA25Ttpe89DFG0XGjyqg2iEnnxCD9sowJz1mFQhio9HGmROVuHmxKhR+7e93sIADtGMWDB8LAyitOKjoxk1r1mxBB1i3SayBsV8F0Z3I30EAhD.PkvqhhHdOmzi9DhdYKfQeBItOx4CvOn65jMue208d.ci0nDhem6u4i76rd0Mev5OjtgGg7v6ug2FOB47m10moDxVJhhFibVbag+os5K9VtwAOiEy5DP0CphZAd1HdOQfudKpkhp2mE32bPjJFAFsYdbqjItcG7ALe1P44wuWOcB2bMrCfNKTDdkJ.up1vaUK3MFH4XAoEMP5V3VdRVjJeFMdtItAGNN6RfyIanXVKZguqDtt.VAWsRH44z8jvfgZTYyUW8dtvW28CWZI3rJV4FF59Qt6x6w3zU7jTXe.YJIADESvOfnjrSpr7iCDcHAtYSHjtZO.AHpr5x4V5Xhz0nwvEVErcZ93J8npgRqrrYY4FzXFFO.roa2Dtm16tB9mxEcppclTDTwSDFI3vF6dfqBRn2couaoxi5vUhopsTfrNIJZk0FrzObouGbvf.C.l5CLVkkScxx2UqYlqpSBB5.otUJh.MFGCH6n3a46OUTx5VIaP4xggq.wKN0Cb896cncP3dtiIxbOWk7b1AFDLosPA7M48vQzPwwzKz1HfRjaEDT2rc.KEOgi1oBciimB5KfLvZV39IBE8PdkTzsz2uj6nS0s6XmKyVAT4XmVWVSNMEqvSB6Pk1wF8BgGcKVO.O45A1kq7LgFqEJ3M3L0gQT9jJhgxhmPsiRYnB9kJsxwqlU4nU.ymJQLn.weFmlIiRAbVI6e9GeseoFZRJuchRI3oJeCrIGpf1lOyf12DO7LbLF3yZrCQQzU.y1PvlLhJULc7yYG5wP+GS8vx3cnwOWIhR2wYYP.3N287ICc3O2q1oCGTSTKzt+2F0BI4K8G9sZJ5IJsUdVJn8ocoxQxOADt.ZxXYbgvbOf9BKv7udZsuk4qftiXmSfw8ord8U5Q+MXjAIkwfAbgZFHV7AhPviD4oyNDrOGrBIxKHJdErwFiEHmsKFz+bPo.6lpZpG4MZJzIS2shGyTmZSM4RqS6rBwagaxTd8GOFWXLXDRguJvXF+j+Bd2tcghr4.bQ7d+iqFxH1t+FF2+dXCGf7.0.F.oX4uhmBEgoP47WmUJmQyLkyQKAu3rUB9bXLt3UEiwEmsCooCuYMm9MNywT7Kvm7Jvw8VFXhw5pHlnVQxPmOv1lEIBHR876IoeSBk6YM+MpoyVZvsyr9bxwztBYXV+jgVZeZOvm1RZSgBp.yUOa0aEJDp9Lduh4fHz9BQztbBDE7sMRy9jXMEDfWSAy.lss3.RLPJudfP2EIexF83BI0PqwVd8jXkHbvFH8xTsTznzdmNeEdyMVA9z8uq+9Q0guV+vKmwWjhZUm9w+BybVpNSX3QtNm3hmk9B94JMhGlD9R.hmZ2sRyT2sKc7N+c5tbfxQhDE7vs4BLPoomjD1BZq3QAj.WvIPymGn3nUMc7p5woOPS49oC9uvmrIqpG6jMY0AShLF2hwa1Em.ZlsIR3pQM70oSm4RTH3mzg9KEUM39zSFHZrYXakbR1hFJ6mRkMlS2F7iAR2lvq8gxaaNTtIVW5I8p7oGIuIdPoH2GSgl7msj8Udi9C8T.DZKI73HQLsZgRrzPVafPbbAoinwZiUiBR2gpR3EMsQzZi1VYOHTT0t6y.gqYKrIgWvXv3BV5.l0g0+9iM8TZQgct+gwdPfQGmKzhIIHl94ZJ6UsULW7Z1h+DhzezlZNktJ3Kc86Mr8RvUSJPPp7.L1hEFEP2Ed9L.tXbJFuMbS3tjj.0.oEez6.AWD0WvYENnOhB0T50iVH+Y70MTJhMqj6T6HZ.E3xjK58qsOvsmHMkklqXQ0K7KDcrmWuC1.WWc8B2WduRYo+u9JkiK0913lhfSMIpl+ihTPTN6OrXZsSPnyx3+G9sZO093sXp46T6oIjfQhtY2f32aj+bxjWbFSOdKbAFjWOp+bK7Hug8LBumkgxkYEHysczbgf647rQekkS3dXMpMZur49Ly3yiH7dTclPCdThxLxAO82YnMOJ3BdQsX+yBbdZSOQ+RtSWjTyqJOQFcXhZR9Agr8SZXa594yhoPW0lBHxBIQaE+kToXTtcSuVk9Itq20SeWb1CvoW855MVeU7SudCPMKrStdCw2FCjfWyMsIp6eLcQeQbGwWD9Hj3IEesm4eyPW5+FoRf8MO8+puLTfGF6V8r+iMg.Y8u1yqnoNihqMuJt97p3Fyqh2edUby4UwGLuJ9vyWQ8co1JA5dZd1.tSYycMukPmguhRnMv+C2qXKYB
So maybe it has something to do with your script. Or have I overlooked something important in terms of functionality? I also add and remove the modulation programmatically.
As I can see, you haven't assigned a matrixTargetId to the slider and, as you write, you haven't connected it to the Value of the Matrix Modulator either. As far as I know, you have to do one of these two things for the system to work as it should.
https://docs.hise.dev/hise-modules/modulators/envelopes/list/matrixmodulator.html
A note:
If you want to control parameters programmatically and use HISE's modulation system, you should activate “deferControllCallback” in the UI slider, as otherwise you may experience hang-ups when adding or removing modulation programmatically.
One more note:
If you want to modulate a parameter using a matrix modulator and add a slider to the UI that is linked to the first slider, you must assign a matrixTargetId to the slider in addition to the connection to the matrix modulator, because otherwise you will not be able to access the modulation system via the second slider. I discussed this with Christoph in this post:
https://forum.hise.audio/topic/13458/matrixid-disappeared-for-linked-sliders