Copy and paste of multiple effects spanning more than one row in the sequencer does not paste to select row

[idleup]

Currently on 2026.15 but issue has been present in at least the last few versions. Mac version, not sure if bug exists in PC version. When effects on multiple sequencer rows and pasting them they jump to rows other than the selected row. It does not seem consistent but it usually will past them between 1 and 3 rows lower than the row you have selected.

[cybercop23]

There were some fixes that went into .15. How are you copying and pasting? Since you're on a Mac, can you record a quick screenshot and explain what you're doing?

[idleup]

Someone on the forum pointed out that it only happens when you select all the effects using a bounding box. If you select them one at a time and then copy and then paste they paste to the destination row.

[idleup]

Screen.Recording.2026-08-18.at.7.40.41.PM.mov

Here is a screenshot of me using my mouse to multi-select and then using command-C to copy selecting a new spot on the same row, and clicking command-v to paste, and you can see it paste it 4 rows below where i had selected...

[cybercop23]

What are you pasting it on? Can you show the left side? Looks like a model with submodels?

[idleup]

Yes, model groups, models, and layers.

[idleup]

By the way, this is just a simple example of only two effects. It was easy to capture. In reality I may have 10 rows of effects that I copy and paste.

[computergeek1507]

Claude Says:

I've dug into this enough to have a solid diagnosis. Here's what I found.

Root cause: This is a regression from the ANCHOR_ROW feature added to preserve empty rows above the first effect when pasting (src-ui-wx/sequencer/MainSequencer.cpp:1535-1541, consumed in src-ui-wx/sequencer/EffectsGrid.cpp:6115-6132).

• When you drag a bounding-box (lasso) selection, EffectsGrid::EstablishSelectionRectangle() (EffectsGrid.cpp:7218) records mRangeStartRow from the raw pixel row where your mouse-down happened (GetRow(mDragStartY)), and that value survives after the drag ends — nothing resets it back to -1.
• On copy, MainSequencer::GetSelectedEffectsData() reads that leftover value via PanelEffectGrid->GetStartRow() and stamps it into the clipboard payload as ANCHOR_ROW:.
• On paste, EffectsGrid::Paste() uses that anchor instead of the row of the actual topmost selected effect to compute drop_row_offset = drop_row - start_row.
• Because a lasso drag is naturally "loose" (you drag from a bit above/left of the first effect to a bit below/right of the last one, you don't pixel-snap to the effect's row), the recorded anchor row usually ends up 1–3 rows above where the first real effect actually sits. That makes drop_row_offset larger than it should be, so everything pastes 1–3 rows lower than the row you clicked — exactly the symptom reported.
• Individual click/ctrl-click selection never touches mRangeStartRow, so GetStartRow() returns -1, no ANCHOR_ROW token is emitted, and the old (correct) "use the first tagged effect's row" logic kicks in — matching the report that one-at-a-time selection pastes correctly.

Where I'd look next for a fix: EstablishSelectionRectangle needs to anchor on the topmost row that actually contains a selected effect, not the raw drag-start pixel row — or GetSelectedEffectsData should only trust the anchor when it's within the set of rows that were actually populated by the selection, falling back to the first tagged effect's row otherwise.

[computergeek1507]

I attempted to fix it for the next version

20260819-1421-49.6200231.mp4