diff --git a/prompt/buffer.go b/prompt/buffer.go
index bf33f33..8328450 100644
--- a/prompt/buffer.go
+++ b/prompt/buffer.go
@@ -9,7 +9,6 @@ type Buffer struct {
 	workingLines    []string // The working lines. Similar to history
 	workingIndex    int
 	CursorPosition  int
-	selectionState  *SelectionState
 	cacheDocument   *Document // TODO: More effective cache using Queue or map. See https://github.com/jonathanslenders/python-prompt-toolkit/blob/master/prompt_toolkit/cache.py#L55-L93
 	preferredColumn int       // Remember the original column for the next up/down movement.
 }
@@ -19,17 +18,14 @@ func (b *Buffer) Text() string {
 	return b.workingLines[b.workingIndex]
 }
 
-// Document method to return document instance from the current text,
-// cursor position and selection state.
+// Document method to return document instance from the current text and cursor position.
 func (b *Buffer) Document() (d *Document) {
 	if b.cacheDocument == nil ||
 		b.cacheDocument.Text != b.Text() ||
-		b.cacheDocument.CursorPosition != b.CursorPosition ||
-		b.cacheDocument.selectionState != b.cacheDocument.selectionState {
+		b.cacheDocument.CursorPosition != b.CursorPosition {
 		b.cacheDocument = &Document{
 			Text:           b.Text(),
 			CursorPosition: b.CursorPosition,
-			selectionState: b.selectionState,
 		}
 	}
 	return b.cacheDocument
diff --git a/prompt/completions.go b/prompt/completions.go
deleted file mode 100644
index 049e6d5..0000000
--- a/prompt/completions.go
+++ /dev/null
@@ -1,24 +0,0 @@
-package prompt
-
-type Completion struct {
-	// The new string that will be inserted into document.
-	text string
-	// Position relative to the cursor position where the new text will start.
-	startPosition int
-}
-
-func (c *Completion) NewCompletionFromPosition(position int) *Completion {
-	if position < c.startPosition {
-		panic("position argument must be smaller than start position.")
-	}
-
-	return &Completion{
-		text: c.text[position-c.startPosition:],
-	}
-}
-
-func NewCompletion(text string) *Completion {
-	return &Completion{
-		text: text,
-	}
-}
diff --git a/prompt/document.go b/prompt/document.go
index 77ae700..c9399fb 100644
--- a/prompt/document.go
+++ b/prompt/document.go
@@ -9,7 +9,6 @@ import (
 type Document struct {
 	Text           string
 	CursorPosition int
-	selectionState *SelectionState
 }
 
 // GetCharRelativeToCursor return character relative to cursor position, or empty string
diff --git a/prompt/selection.go b/prompt/selection.go
deleted file mode 100644
index 206776f..0000000
--- a/prompt/selection.go
+++ /dev/null
@@ -1,19 +0,0 @@
-package prompt
-
-// SelectionType expresses how characters selected.
-type SelectionType int
-
-const (
-	// CHARACTERS selected freely.
-	CHARACTERS SelectionType = iota
-	// LINES selected current line.
-	LINES
-	// BLOCK selected the word block.
-	BLOCK
-)
-
-// SelectionState holds cursor position and selected characters.
-type SelectionState struct {
-	OriginalCursorPosition int
-	Type                   SelectionType
-}
diff --git a/prompt/selectiontype_string.go b/prompt/selectiontype_string.go
deleted file mode 100644
index 228ab3c..0000000
--- a/prompt/selectiontype_string.go
+++ /dev/null
@@ -1,16 +0,0 @@
-// Code generated by "stringer -type SelectionType selection.go"; DO NOT EDIT
-
-package prompt
-
-import "fmt"
-
-const _SelectionType_name = "CHARACTERSLINESBLOCK"
-
-var _SelectionType_index = [...]uint8{0, 10, 15, 20}
-
-func (i SelectionType) String() string {
-	if i < 0 || i >= SelectionType(len(_SelectionType_index)-1) {
-		return fmt.Sprintf("SelectionType(%d)", i)
-	}
-	return _SelectionType_name[_SelectionType_index[i]:_SelectionType_index[i+1]]
-}