Ensure maximumDimensions have changes before firing onDidChangeMaximumDimensions

Fixes #52916

src/vs/workbench/api/node/extHostTerminalService.ts

@@ -214,6 +214,9 @@ export class ExtHostTerminalRenderer extends BaseExtHostTerminal implements vsco
 	}
 
 	public _setMaximumDimensions(columns: number, rows: number): void {
+		if (this._maximumDimensions && this._maximumDimensions.columns === columns && this._maximumDimensions.rows === rows) {
+			return;
+		}
 		this._maximumDimensions = { columns, rows };
 		this._onDidChangeMaximumDimensions.fire(this.maximumDimensions);
 	}

src/vs/workbench/parts/terminal/electron-browser/terminalInstance.ts

@@ -963,7 +963,7 @@ export class TerminalInstance implements ITerminalInstance {
 				this._safeSetOption('drawBoldTextInBrightColors', config.drawBoldTextInBrightColors);
 			}
 
-			if (cols !== this._xterm.getOption('cols') || rows !== this._xterm.getOption('rows')) {
+			if (cols !== this._xterm.cols || rows !== this._xterm.rows) {
 				this._onDimensionsChanged.fire();
 			}