fix zero height output height.

src/vs/workbench/contrib/notebook/browser/notebookBrowser.ts

@@ -118,6 +118,7 @@ export interface ICellOutputViewModel {
 	resolveMimeTypes(textModel: NotebookTextModel, kernelProvides: readonly string[] | undefined): [readonly IOrderedMimeType[], number];
 	pickedMimeType: number;
 	supportAppend(): boolean;
+	hasMultiMimeType(): boolean;
 	toRawJSON(): any;
 }
 

src/vs/workbench/contrib/notebook/browser/viewModel/cellOutputViewModel.ts

@@ -33,6 +33,15 @@ export class CellOutputViewModel extends Disposable implements ICellOutputViewMo
 		super();
 	}
 
+	hasMultiMimeType() {
+		if (this._outputRawData.outputs.length < 2) {
+			return false;
+		}
+
+		const firstMimeType = this._outputRawData.outputs[0].mime;
+		return this._outputRawData.outputs.some(output => output.mime !== firstMimeType);
+	}
+
 	supportAppend() {
 		// if there is any mime type that's not mergeable then the whole output is not mergeable.
 		return this._outputRawData.outputs.every(op => mimeTypeIsMergeable(op.mime));

src/vs/workbench/contrib/notebook/browser/viewModel/codeCellViewModel.ts

@@ -343,6 +343,10 @@ export class CodeCellViewModel extends BaseCellViewModel implements ICellViewMod
 		}
 
 		this._ensureOutputsTop();
+		if (height < 28 && this._outputViewModels[index].hasMultiMimeType()) {
+			height = 28;
+		}
+
 		this._outputCollection[index] = height;
 		if (this._outputsTop!.changeValue(index, height)) {
 			this.layoutChange({ outputHeight: true }, source);