1. Added custom border-highlight handlers:

      • Added  SetBorderColor(tcell.Color)  to  FileBrowserComponent  in file_browser.go.
      • Added  SetBorderColor(tcell.Color)  to  DatasetInfoComponent  in dataset_info.go.
      • Added  SetBorderColor(tcell.Color)  to  SnapshotBrowserComponent  in snapshot_browser.go.
      • Added  SetBorderColor(tcell.Color)  wrapper inside  LoadingContainer  in data_loader.go.
  2. Implemented coordinate tracking and resize interaction in main_page.go:
      • Configured  SetMouseCapture  on the parent  windowLayout .
      • Used absolute screen coordinates from  event.Position()  and checked them against the widget rectangles returned by  GetRect() .
      • Enabled interactive boundary hover detection: highlighting the border of adjacent windows with  theme.Primary  (accent orange) when
      the mouse is positioned on the boundaries.
      • Handled  MouseLeftDown  click drags to dynamically scale flex row/column proportions using  tview.Flex.ResizeItem , clamping panels
      to safe minimum boundaries (minimum 10 columns for browser width, 4 rows for dataset info height, 5 rows for snapshot browser height).
      • Released state tracking on  MouseLeftUp  or when buttons are released.

Author: markusressel

internal/ui/dataset_info/dataset_info.go

@@ -212,6 +212,13 @@ func (datasetInfo *DatasetInfoComponent) GetLayout() *uiutil.LoadingContainer {
 	return datasetInfo.container
 }
 
+func (datasetInfo *DatasetInfoComponent) SetBorderColor(color tcell.Color) {
+	datasetInfo.textView.SetBorderColor(color)
+	if datasetInfo.container != nil {
+		datasetInfo.container.SetBorderColor(color)
+	}
+}
+
 func (datasetInfo *DatasetInfoComponent) CreateSnapshot(name string) error {
 	if datasetInfo.dataset == nil {
 		return fmt.Errorf("no dataset selected")

internal/ui/file_browser/file_browser.go

@@ -888,6 +888,12 @@ func (fileBrowser *FileBrowserComponent) GetLayout() tview.Primitive {
 	return fileBrowser.layout
 }
 
+func (fileBrowser *FileBrowserComponent) SetBorderColor(color tcell.Color) {
+	if flex, ok := fileBrowser.tableContainer.GetLayout().(*tview.Flex); ok {
+		flex.SetBorderColor(color)
+	}
+}
+
 func (fileBrowser *FileBrowserComponent) SelectHeader() {
 	fileBrowser.tableContainer.SelectHeader()
 }

internal/ui/main_page.go

@@ -8,13 +8,30 @@ import (
 	"zfs-file-history/internal/ui/shortcut_helper"
 	"zfs-file-history/internal/ui/snapshot_browser"
 	"zfs-file-history/internal/ui/status_message"
+	"zfs-file-history/internal/ui/theme"
 	uiutil "zfs-file-history/internal/ui/util"
 	"zfs-file-history/internal/zfs"
 
 	"github.com/gdamore/tcell/v2"
 	"github.com/rivo/tview"
 )
 
+type dragType int
+
+const (
+	dragNone dragType = iota
+	dragVertical
+	dragHorizontal
+)
+
+type boundaryType int
+
+const (
+	boundaryNone boundaryType = iota
+	boundaryVertical
+	boundaryHorizontal
+)
+
 type MainPage struct {
 	application     *tview.Application
 	header          *ApplicationHeaderComponent
@@ -23,8 +40,14 @@ type MainPage struct {
 	datasetInfo     *dataset_info.DatasetInfoComponent
 	snapshotBrowser *snapshot_browser.SnapshotBrowserComponent
 	layout          *tview.Flex
+	windowLayout    *tview.Flex
+	infoLayout      *tview.Flex
 
 	wasInitialized bool
+
+	isDragging      bool
+	dragType        dragType
+	hoveredBoundary boundaryType
 }
 
 func NewMainPage(application *tview.Application, path string) *MainPage {
@@ -143,6 +166,105 @@ func (mainPage *MainPage) createLayout() *tview.Flex {
 
 	mainPageLayout.AddItem(windowLayout, 0, 1, true)
 
+	mainPage.windowLayout = windowLayout
+	mainPage.infoLayout = infoLayout
+
+	windowLayout.SetMouseCapture(func(action tview.MouseAction, event *tcell.EventMouse) (tview.MouseAction, *tcell.EventMouse) {
+		mouseX, mouseY := event.Position()
+		buttons := event.Buttons()
+
+		diX, diY, diW, diH := mainPage.datasetInfo.GetLayout().GetRect()
+		_, sbY, _, sbH := mainPage.snapshotBrowser.GetLayout().GetRect()
+		winX, _, winW, _ := windowLayout.GetRect()
+
+		// 1. If currently dragging
+		if mainPage.isDragging {
+			if buttons == tcell.ButtonNone || action == tview.MouseLeftUp {
+				mainPage.isDragging = false
+				mainPage.dragType = dragNone
+				mainPage.hoveredBoundary = boundaryNone
+				mainPage.updateBorderHighlights()
+				return tview.MouseConsumed, nil
+			}
+
+			if mainPage.dragType == dragVertical {
+				newLeftWidth := mouseX - winX
+				minWidth := 10
+				if newLeftWidth < minWidth {
+					newLeftWidth = minWidth
+				}
+				if newLeftWidth > winW-minWidth {
+					newLeftWidth = winW - minWidth
+				}
+				newRightWidth := winW - newLeftWidth
+
+				windowLayout.ResizeItem(mainPage.fileBrowser.GetLayout(), 0, newLeftWidth)
+				windowLayout.ResizeItem(infoLayout, 0, newRightWidth)
+			} else if mainPage.dragType == dragHorizontal {
+				infoH := diH + sbH
+				infoY := diY
+				newTopHeight := mouseY - infoY
+				minTopHeight := 4
+				minBottomHeight := 5
+				if newTopHeight < minTopHeight {
+					newTopHeight = minTopHeight
+				}
+				if newTopHeight > infoH-minBottomHeight {
+					newTopHeight = infoH - minBottomHeight
+				}
+				newBottomHeight := infoH - newTopHeight
+
+				infoLayout.ResizeItem(mainPage.datasetInfo.GetLayout(), 0, newTopHeight)
+				infoLayout.ResizeItem(mainPage.snapshotBrowser.GetLayout(), 0, newBottomHeight)
+			}
+
+			return tview.MouseConsumed, nil
+		}
+
+		// 2. Not dragging: detect hover boundaries
+		isOnVertical := false
+		if mouseY >= diY && mouseY < sbY+sbH {
+			if mouseX == diX || mouseX == diX-1 {
+				isOnVertical = true
+			}
+		}
+
+		isOnHorizontal := false
+		if mouseX >= diX && mouseX < diX+diW {
+			if mouseY == sbY || mouseY == sbY-1 {
+				isOnHorizontal = true
+			}
+		}
+
+		newHover := boundaryNone
+		if isOnHorizontal {
+			newHover = boundaryHorizontal
+		} else if isOnVertical {
+			newHover = boundaryVertical
+		}
+
+		if newHover != mainPage.hoveredBoundary {
+			mainPage.hoveredBoundary = newHover
+			mainPage.updateBorderHighlights()
+			return tview.MouseConsumed, nil
+		}
+
+		// 3. Initiate dragging
+		if buttons&tcell.Button1 != 0 && action == tview.MouseLeftDown {
+			if isOnHorizontal {
+				mainPage.isDragging = true
+				mainPage.dragType = dragHorizontal
+				return tview.MouseConsumed, nil
+			} else if isOnVertical {
+				mainPage.isDragging = true
+				mainPage.dragType = dragVertical
+				return tview.MouseConsumed, nil
+			}
+		}
+
+		return action, event
+	})
+
 	mainPage.header = header
 
 	shortcutMap := shortcut_helper.NewShortcutMap(mainPage.application)
@@ -218,3 +340,33 @@ func (mainPage *MainPage) updateShortcutMap(component FocusableUiComponent) {
 		mainPage.clearShortcutMap()
 	}
 }
+
+func (mainPage *MainPage) setPanelBorderColor(panel FocusableUiComponent, color tcell.Color) {
+	if fb, ok := panel.(*file_browser.FileBrowserComponent); ok {
+		fb.SetBorderColor(color)
+	} else if di, ok := panel.(*dataset_info.DatasetInfoComponent); ok {
+		di.SetBorderColor(color)
+	} else if sb, ok := panel.(*snapshot_browser.SnapshotBrowserComponent); ok {
+		sb.SetBorderColor(color)
+	}
+}
+
+func (mainPage *MainPage) updateBorderHighlights() {
+	defaultColor := theme.Colors.Layout.Border
+	highlightColor := theme.Primary
+
+	switch mainPage.hoveredBoundary {
+	case boundaryVertical:
+		mainPage.setPanelBorderColor(mainPage.fileBrowser, highlightColor)
+		mainPage.setPanelBorderColor(mainPage.datasetInfo, highlightColor)
+		mainPage.setPanelBorderColor(mainPage.snapshotBrowser, highlightColor)
+	case boundaryHorizontal:
+		mainPage.setPanelBorderColor(mainPage.fileBrowser, defaultColor)
+		mainPage.setPanelBorderColor(mainPage.datasetInfo, highlightColor)
+		mainPage.setPanelBorderColor(mainPage.snapshotBrowser, highlightColor)
+	case boundaryNone:
+		mainPage.setPanelBorderColor(mainPage.fileBrowser, defaultColor)
+		mainPage.setPanelBorderColor(mainPage.datasetInfo, defaultColor)
+		mainPage.setPanelBorderColor(mainPage.snapshotBrowser, defaultColor)
+	}
+}

internal/ui/snapshot_browser/snapshot_browser.go

@@ -202,6 +202,15 @@ func (snapshotBrowser *SnapshotBrowserComponent) GetLayout() *uiutil.LoadingCont
 	return snapshotBrowser.container
 }
 
+func (snapshotBrowser *SnapshotBrowserComponent) SetBorderColor(color tcell.Color) {
+	if flex, ok := snapshotBrowser.tableContainer.GetLayout().(*tview.Flex); ok {
+		flex.SetBorderColor(color)
+	}
+	if snapshotBrowser.container != nil {
+		snapshotBrowser.container.SetBorderColor(color)
+	}
+}
+
 func (snapshotBrowser *SnapshotBrowserComponent) SetPath(path string, force bool) {
 	if !force && snapshotBrowser.path == path {
 		return

internal/ui/util/data_loader.go

@@ -5,6 +5,7 @@ import (
 	"sync"
 	"sync/atomic"
 
+	"github.com/gdamore/tcell/v2"
 	"github.com/rivo/tview"
 )
 
@@ -112,3 +113,16 @@ func (c *LoadingContainer) SetIsLoading(isLoading bool) {
 func (c *LoadingContainer) GetFrontPage() (string, tview.Primitive) {
 	return c.Pages.GetFrontPage()
 }
+
+func (c *LoadingContainer) SetBorderColor(color tcell.Color) {
+	if c.loadingView != nil {
+		c.loadingView.SetBorderColor(color)
+	}
+	if c.content != nil {
+		if box, ok := c.content.(interface{ SetBorderColor(tcell.Color) *tview.Box }); ok {
+			box.SetBorderColor(color)
+		} else if flex, ok := c.content.(*tview.Flex); ok {
+			flex.SetBorderColor(color)
+		}
+	}
+}