This is / was one of the high demanded features. There are several looong threads in this forum section on the subject, including a recent one. I will not go in details of those threads. This is simply a concept of how it can be done visually from user standpoint. This is what I came up with.

To have a multi-function "freeze" (snowflake) button. Press once, turns "blue" - regular freeze. Click on it second time- turns orange, which means it will be ready for partial bar freeze/unfreeze. Click again - clears it.

So the way I see it can work is this. You click snowflake till it turns orange, only on the channels that you want to do this "partial" freeze. Select the bars that you want to freeze->right click on selected->freeze section (or unfreeze section). Frozen section(s) will have slim bar on the top, indicating they are "frozen".

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