Cursor position after adding preset in sequence mode causes an incorrect sequence formation

#6272

Author: rrodionov91

packages/ketcher-core/src/application/editor/modes/SequenceMode.ts

@@ -1676,7 +1676,6 @@ export class SequenceMode extends BaseMode {
     const history = new EditorHistory(editor);
     const modelChanges = new Command();
     const selections = SequenceRenderer.selections;
-    const wasCanvasEmptyBeforeInsertion = SequenceRenderer.isEmptyCanvas();
 
     if (selections.length > 0) {
       if (this.isSelectionsContainAntisenseChains(selections)) {
@@ -1760,11 +1759,6 @@ export class SequenceMode extends BaseMode {
       );
       history.update(modelChanges);
     }
-
-    if (wasCanvasEmptyBeforeInsertion) {
-      this.turnOnEditMode();
-      SequenceRenderer.moveCaretForward();
-    }
   }
 
   private createRnaPresetNode(preset: IRnaPreset, position: Vec2) {

packages/ketcher-core/src/application/render/renderers/sequence/SequenceRenderer.ts

@@ -468,8 +468,8 @@ export class SequenceRenderer {
 
     SequenceRenderer.forEachNode(({ twoStrandedNode, nodeIndexOverall }) => {
       if (
-        twoStrandedNode.senseNode?.monomer === monomer ||
-        twoStrandedNode.antisenseNode?.monomer === monomer
+        twoStrandedNode.senseNode?.monomers.includes(monomer) ||
+        twoStrandedNode.antisenseNode?.monomers.includes(monomer)
       ) {
         newCaretPosition = nodeIndexOverall;
       }
@@ -483,8 +483,8 @@ export class SequenceRenderer {
 
     SequenceRenderer.forEachNode(({ twoStrandedNode, nodeIndexOverall }) => {
       if (
-        twoStrandedNode.senseNode?.monomer === monomer ||
-        twoStrandedNode.antisenseNode?.monomer === monomer
+        twoStrandedNode.senseNode?.monomers.includes(monomer) ||
+        twoStrandedNode.antisenseNode?.monomers.includes(monomer)
       ) {
         newCaretPosition = nodeIndexOverall;
       }
@@ -1154,8 +1154,8 @@ export class SequenceRenderer {
 
     SequenceRenderer.forEachNode(({ twoStrandedNode }) => {
       if (
-        twoStrandedNode.senseNode?.monomer === monomer ||
-        twoStrandedNode.antisenseNode?.monomer === monomer
+        twoStrandedNode.senseNode?.monomers.includes(monomer) ||
+        twoStrandedNode.antisenseNode?.monomers.includes(monomer)
       ) {
         rendererToReturn =
           twoStrandedNode.senseNode?.renderer ||