From 30ea81d0fbb2c88bdc40acf4da64a072fe2ad42f Mon Sep 17 00:00:00 2001
From: Meinzzzz <lukas.geiselhart35@gmail.com>
Date: Mon, 8 Dec 2025 22:59:08 +0100
Subject: [PATCH] Improve virtual keyboard logic and fix Tab issues

---
 .../ckeditor5-math/src/ui/mainformview.ts     | 28 +++++------
 .../ckeditor5-math/src/ui/mathinputview.ts    | 49 ++++++++++++++++---
 2 files changed, 55 insertions(+), 22 deletions(-)

diff --git a/packages/ckeditor5-math/src/ui/mainformview.ts b/packages/ckeditor5-math/src/ui/mainformview.ts
index cb96826a09..2c327517ce 100644
--- a/packages/ckeditor5-math/src/ui/mainformview.ts
+++ b/packages/ckeditor5-math/src/ui/mainformview.ts
@@ -134,42 +134,42 @@ export default class MainFormView extends View {
 	public set equation( equation: string ) {
 		const norm = equation.trim();
 		this.mathInputView.value = norm.length ? norm : null;
-		if ( this.mathView ) this.mathView.value = norm;
+		if ( this.mathView ) {
+			this.mathView.value = norm;
+		}
 	}
 
 	public focus(): void {
 		this._focusCycler.focusFirst();
 	}
 
-	/** Handle delimiter stripping and preview updates. */
-	private _setupSync(previewEnabled: boolean): void {
-		this.mathInputView.on('change:value', () => {
-			let eq = (this.mathInputView.value ?? '').trim();
+	private _setupSync( previewEnabled: boolean ): void {
+		this.mathInputView.on( 'change:value', () => {
+			let eq = ( this.mathInputView.value ?? '' ).trim();
 
-			// Strip delimiters if present (e.g. pasted content)
-			if (hasDelimiters(eq)) {
-				const params = extractDelimiters(eq);
+			if ( hasDelimiters( eq ) ) {
+				const params = extractDelimiters( eq );
 				eq = params.equation;
 				this.displayButtonView.isOn = params.display;
 
-				// Update the input with stripped delimiters
-				if (this.mathInputView.value !== eq) {
+				if ( this.mathInputView.value !== eq ) {
 					this.mathInputView.value = eq.length ? eq : null;
 				}
 			}
 
-			// Update preview
-			if (previewEnabled && this.mathView && this.mathView.value !== eq) {
+			if ( previewEnabled && this.mathView && this.mathView.value !== eq ) {
 				this.mathView.value = eq;
 			}
-		});
+		} );
 	}
 
 	private _createButton( label: string, icon: string, className: string, type?: 'submit' | 'button' ): ButtonView {
 		const btn = new ButtonView( this.locale );
 		btn.set( { label, icon, tooltip: true } );
 		btn.extendTemplate( { attributes: { class: className } } );
-		if (type) btn.type = type;
+		if ( type ) {
+			btn.type = type;
+		}
 		return btn;
 	}
 
diff --git a/packages/ckeditor5-math/src/ui/mathinputview.ts b/packages/ckeditor5-math/src/ui/mathinputview.ts
index 7df5c590df..b296c86aae 100644
--- a/packages/ckeditor5-math/src/ui/mathinputview.ts
+++ b/packages/ckeditor5-math/src/ui/mathinputview.ts
@@ -84,6 +84,11 @@ export default class MathInputView extends View {
 		textarea.value = this.value ?? '';
 		textarea.readOnly = this.isReadOnly;
 
+		if ( this.mathfield ) {
+			this.mathfield.remove();
+			this.mathfield = null;
+		}
+
 		textarea.addEventListener( 'input', () => {
 			const val = textarea.value;
 			if ( this.mathfield ) {
@@ -92,11 +97,30 @@ export default class MathInputView extends View {
 			this.value = val || null;
 		} );
 
+		this.on( 'change:value', ( _e, _n, val ) => {
+			const newVal = val ?? '';
+			textarea.value = newVal;
+			if ( this.mathfield && this.mathfield.value !== newVal ) {
+				this.mathfield.setValue( newVal, { silenceNotifications: true } );
+			}
+		} );
+
 		this.on( 'change:isReadOnly', ( _e, _n, val ) => {
 			textarea.readOnly = val;
-			if ( this.mathfield ) { this.mathfield.readOnly = val; }
+			if ( this.mathfield ) {
+				this.mathfield.readOnly = val;
+			}
 		} );
 
+		const vk = ( window as any ).mathVirtualKeyboard;
+		if ( vk ) {
+			vk.addEventListener( 'geometrychange', () => {
+				if ( vk.visible && document.activeElement === textarea && this.mathfield ) {
+					this.mathfield.focus();
+				}
+			} );
+		}
+
 		this._loadMathLive();
 	}
 
@@ -111,17 +135,23 @@ export default class MathInputView extends View {
 				MathfieldClass.plonkSound = null;
 			}
 
-			if ( this.element ) { this._createMathField(); }
+			if ( this.element ) {
+				this._createMathField();
+			}
 		} catch ( e ) {
 			console.error( 'MathLive load failed:', e );
 			const c = this.element?.querySelector( '.ck-mathlive-container' );
-			if ( c ) { c.textContent = 'Math editor unavailable'; }
+			if ( c ) {
+				c.textContent = 'Math editor unavailable';
+			}
 		}
 	}
 
 	private _createMathField(): void {
 		const container = this.element?.querySelector( '.ck-mathlive-container' );
-		if ( !container ) { return; }
+		if ( !container ) {
+			return;
+		}
 
 		const mf = document.createElement( 'math-field' ) as MathFieldElement;
 		mf.mathVirtualKeyboardPolicy = 'auto';
@@ -131,8 +161,6 @@ export default class MathInputView extends View {
 
 		mf.addEventListener( 'mount', () => {
 			mf.inlineShortcuts = { ...mf.inlineShortcuts, dx: 'dx', dy: 'dy', dt: 'dt' };
-			const btn = mf.shadowRoot?.querySelector( '[part="virtual-keyboard-toggle"]' ) as HTMLElement;
-			btn?.addEventListener( 'click', () => mf.focus() );
 		}, { once: true } );
 
 		mf.addEventListener( 'input', () => {
@@ -153,13 +181,18 @@ export default class MathInputView extends View {
 
 	public hideKeyboard(): void {
 		const vk = ( window as any ).mathVirtualKeyboard;
-		if ( vk?.visible ) { vk.hide(); }
+		if ( vk?.visible ) {
+			vk.hide();
+		}
 	}
 
 	public override destroy(): void {
 		this.hideKeyboard();
 		if ( this.mathfield ) {
-			try { this.mathfield.blur(); this.mathfield.remove(); } catch { /* ignore */ }
+			try {
+				this.mathfield.blur();
+				this.mathfield.remove();
+			} catch { /* ignore */ }
 			this.mathfield = null;
 		}
 		super.destroy();