Summary
The terminal pane lacks scrollback and text selection capabilities. Users cannot scroll through terminal history or select/copy text in the embedded terminal view.
Background
Discovered while fixing mouse event leak bugs (#92, #96, #98). Deep investigation revealed the root cause.
Root Cause Analysis
Why Scrolling Doesn't Work
| Component |
Limitation |
| vt10x |
No scrollback buffer - terminal history is discarded when it scrolls off screen |
| bubbletea |
Uses alternate screen mode (WithAltScreen) which has no native scrollback |
| Mouse capture |
Bubbletea captures all mouse events - they can't fall through to host terminal |
The Paradox Explained
When Claude Code runs directly in a terminal:
- Host terminal (iTerm, etc.) maintains scrollback buffer
- Mouse wheel scrolls the terminal's buffer
- Works because the terminal handles it, not the app
When Claude Code runs inside OpenKanban:
- OpenKanban's terminal pane (vt10x) has no scrollback
- Alternate screen mode disables host terminal scrollback
- Mouse events captured by bubbletea can't reach host terminal
- No scrollback buffer exists anywhere in the chain
Current Behavior
| Mouse Action |
Behavior |
| Click |
Blocked (prevents garbage) |
| Scroll wheel |
Blocked (no scrollback to scroll) |
| Click-drag |
Nothing (no selection infrastructure) |
| Motion |
Blocked (prevents garbage) |
Solution Options
Option A: Implement Scrollback in Pane (Recommended)
Add scrollback buffer to the Pane struct:
- Maintain history buffer (vt10x doesn't support this)
- Intercept scroll-up before lines are discarded
- Track viewport offset
- Render from scrollback when scrolled up
- Handle scroll wheel to adjust viewport
Option B: Migrate to bubbleterm
Replace vt10x with bubbleterm:
- Built-in scrollback support ✅
- Designed for bubbletea integration ✅
- Handles mouse events properly ✅
- More significant refactor
Option C: Hybrid Approach
- Use bubbleterm for terminal emulation
- Keep existing pane management
- Leverage bubbleterm's scrollback and mouse handling
Implementation Requirements (Option A)
1. Scrollback Buffer
type Pane struct {
// ... existing fields
scrollbackBuffer [][]vt10x.Glyph // historical lines
scrollbackMax int // max lines to keep (e.g., 10000)
viewportOffset int // 0 = bottom (live), >0 = scrolled up
}2. Line Capture
Intercept when vt10x scrolls content off the top of the screen and save to buffer.
3. Scroll Handling
func (p *Pane) HandleScroll(direction int) {
if direction < 0 { // scroll up
p.viewportOffset = min(p.viewportOffset + 3, len(p.scrollbackBuffer))
} else { // scroll down
p.viewportOffset = max(p.viewportOffset - 3, 0)
}
}4. Render Modification
When viewportOffset > 0, render from scrollback buffer instead of live vt10x screen.
Text Selection (Separate but Related)
Once scrollback exists, selection becomes feasible:
- Track selection start/end coordinates
- Render selected text with inverted colors
- Copy to clipboard on release
References
Summary
The terminal pane lacks scrollback and text selection capabilities. Users cannot scroll through terminal history or select/copy text in the embedded terminal view.
Background
Discovered while fixing mouse event leak bugs (#92, #96, #98). Deep investigation revealed the root cause.
Root Cause Analysis
Why Scrolling Doesn't Work
WithAltScreen) which has no native scrollbackThe Paradox Explained
When Claude Code runs directly in a terminal:
When Claude Code runs inside OpenKanban:
Current Behavior
Solution Options
Option A: Implement Scrollback in Pane (Recommended)
Add scrollback buffer to the
Panestruct:Option B: Migrate to bubbleterm
Replace vt10x with bubbleterm:
Option C: Hybrid Approach
Implementation Requirements (Option A)
1. Scrollback Buffer
2. Line Capture
Intercept when vt10x scrolls content off the top of the screen and save to buffer.
3. Scroll Handling
4. Render Modification
When
viewportOffset > 0, render from scrollback buffer instead of live vt10x screen.Text Selection (Separate but Related)
Once scrollback exists, selection becomes feasible:
References